Supplemental Prospectus (Form 424B5)

Filed Pursuant to Rule 424(b)(5)
Registration Statement No. 333-277778

PROSPECTUS SUPPLEMENT

(To Prospectus dated March 8, 2024, as amended October 23, 2026)

Up to 222,000,000 Rights for Up to 37,000,000 Common Shares

Issuable Upon the Exercise of

Transferable Subscription Rights to Purchase Common Shares

Nuveen Municipal High Income Opportunity Fund

Nuveen Municipal High Income Opportunity Fund (the "Fund"), a diversified, closed-end management investment company, is issuing up to 222,000,000 transferable subscription rights (the "Rights") to its common shareholders (the "Common Shareholders") to subscribe for an aggregate of up to 37,000,000 common shares, $0.01 par value per share (each, a "Common Share," and collectively, the "Common Shares"), pursuant to this prospectus supplement. The actual number of Rights and Common Shares issued will be based upon the total number of Common Shares outstanding as of the Record Date (as defined below), which will be impacted by certain events, such as the issuance of new Common Shares pursuant to the Fund's dividend reinvestment plan or the Fund's current at-the-market offering of Common Shares.

Common Shares are listed on the New York Stock Exchange (the "NYSE") under the symbol "NMZ." Common Shareholders of record on November 2, 2026 (the "Record Date") will receive one Right for each Common Share held. These Rights are transferable and will allow the holders thereof to purchase additional Common Shares. The Rights will be listed for trading on the NYSE under the symbol "NMZ RT" during the course of the Rights offering.

The Rights entitle the holders to purchase one new Common Share for every six Rights held (1 for 6) (the "Primary Subscription"). Record Date Common Shareholders ("Record Date Shareholders") who fully exercise their Rights will be entitled to over-subscribe for additional Common Shares covered by any unexercised Rights in the Primary Subscription, subject to certain limitations and subject to allotment. In addition, the Fund, subject to approval by the Board of Trustees of the Fund (the "Board"), may increase the number of Common Shares available for subscription by up to 25%, or up to an additional 9,250,000 Common Shares, for an aggregate total of up to 46,250,000 Common Shares. See "Description of the Rights Offering-Primary and Secondary Over-Subscription Privileges." Fractional shares will not be issued upon exercise of Rights. Accordingly, Common Shares may be purchased only pursuant to the exercise of Rights in integral multiples of six. The number of Rights issued to a Record Date Shareholder will be rounded up to the nearest number of Rights evenly divisible by six.

The subscription price per Common Share (the "Subscription Price") will be determined based upon a formula equal to 95% of the average of the last reported sales price of the Common Shares on the NYSE on the Expiration Date (as defined below) and each of the four (4) preceding trading days (the "Formula Price"). If, however, the Formula Price is less than 90% of the net asset value ("NAV") per Common Share at the close of trading on the NYSE on the Expiration Date, then the Subscription Price will be 90% of the Fund's NAV per Common Share at the close of trading on the NYSE on the Expiration Date. The Rights offering will expire at 5:00 p.m., Eastern Time, on December 2, 2026 (the "Expiration Date").

		Per Common Share			Total(1)
Estimated subscription price of Common Shares to shareholders exercising Rights(2)		$	8.60		$	318,200,000
Estimated sales load			-			-
Estimated proceeds, before expenses, to the Fund(3)		$	8.60		$	318,200,000

	(1)	Assumes that all Rights are exercised at the estimated Subscription Price (as described below). All of the Rights may not be exercised, and the estimated Subscription Price may be higher or lower than the actual Subscription Price.
	(2)	The estimated Subscription Price to the public is based upon 95% of the average of the last reported sales price of the Fund's Common Shares on the NYSE on October 16, 2026 and each of the four (4) preceding trading days. See "Terms of the Rights Offering-Subscription Price."
	(3)	Nuveen Fund Advisors, LLC ("Nuveen Fund Advisors"), and not the Fund or its Common Shareholders, will bear all expenses incurred in connection with the Rights offering. Offering expenses borne by Nuveen Fund Advisors are estimated to be approximately $371,000 in the aggregate.

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The Common Shares are expected to be ready for delivery in book-entry form through the Depository Trust Company on or about December 9, 2026, unless extended.

The closing price for the Common Shares on the NYSE on October 16, 2026 was $9.13. The NAV of the Common Shares at the close of business on October 16, 2026 was $9.28 per Common Share.

Investing in the Common Shares through Rights involves risks. See "Risk Factors" beginning on page 13 of the accompanying prospectus and "Special Characteristics and Risks of the Rights Offering" beginning on page 20 in this prospectus supplement. You should consider carefully these risks together with all of the other information in this prospectus supplement and the accompanying prospectus before making a decision to invest in Common Shares through Rights.

SHAREHOLDERS WHO DO NOT FULLY EXERCISE THEIR RIGHTS MAY, AT THE COMPLETION OF THE RIGHTS OFFERING, OWN A SMALLER PROPORTIONAL INTEREST IN THE FUND THAN IF THEY EXERCISED THEIR RIGHTS. AS A RESULT OF THE RIGHTS OFFERING YOU MAY EXPERIENCE SUBSTANTIAL DILUTION OF THE AGGREGATE NET ASSET VALUE OF YOUR COMMON SHARES. ALL COSTS OF THE OFFERING WILL BE BORNE BY NUVEEN FUND ADVISORS, AND NOT THE FUND OR COMMON SHAREHOLDERS. RIGHTS EXERCISED BY A RIGHTS HOLDER ARE IRREVOCABLE.

The Fund expects to declare monthly distributions payable on December 1, 2026 and December 31, 2026, with record dates of November 13, 2026 and December 2, 2026, respectively. Any Common Shares issued after such record dates as a result of the Rights offering will not be record date Common Shares for the Fund's monthly distributions to be paid on December 1, 2026 and December 31, 2026 and will not be entitled to receive such distributions.

The date of this prospectus supplement is October 23, 2026.

You should read this prospectus supplement, together with the accompanying prospectus, which contains important information about the Fund, before deciding whether to invest in Common Shares through Rights and retain it for future reference. A statement of additional information, dated March 8, 2024, and as it may be supplemented (the "SAI"), containing additional information about the Fund, has been filed with the SEC and is incorporated by reference in its entirety into this prospectus supplement and the accompanying prospectus. This prospectus supplement, the accompanying prospectus and the SAI are part of a "shelf" registration statement filed with the SEC. This prospectus supplement describes the specific details regarding this offering. If information in this prospectus supplement is inconsistent with the accompanying prospectus or the SAI, you should rely on this prospectus supplement. You may request a free copy of the SAI, annual and semi-annual reports to shareholders, and other information about the Fund, and make shareholder inquiries by calling (800) 257-8787 or by writing to the Fund at 333 West Wacker Drive, Chicago, Illinois 60606, or from the Fund's website (www.nuveen.com). The information contained in, or that can be accessed through, the Fund's website is not part of this prospectus supplement, the accompanying prospectus or the SAI, except to the extent specifically incorporated by reference herein. You also may obtain a copy of the SAI (and other information regarding the Fund) from the SEC's website (www.sec.gov).

You should not construe the contents of this prospectus supplement and the accompanying prospectus as legal, tax or financial advice. You should consult with your own professional advisors as to the legal, tax, financial or other matters relevant to the suitability of an investment in the Common Shares through Rights.

Common Shares do not represent a deposit or obligation of, and are not guaranteed or endorsed by, any bank or other insured depository institution, and are not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency.

Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

TABLE OF CONTENTS

Prospectus Supplement

		Page
Forward-Looking Statements			ii
Prospectus Supplement Summary			S-1
Description of the Rights Offering			S-6
Summary of Fund Expenses			S-16
Trading and Net Asset Value Information			S-18
Use of Proceeds			S-18
Capitalization			S-19
Special Characteristics and Risks of the Rights Offering			S-20
Taxation			S-23
Legal Matters			S-24
Available Information			S-24

Prospectus

Prospectus Summary			1
Summary of Fund Expenses			7
Financial Highlights			7
Trading and Net Asset Value Information			7
The Fund			7
Use of Proceeds			8
The Fund's Investments			8
Use of Leverage			9
Risk Factors			13
Management of the Fund			13
Net Asset Value			16
Distributions			17
Dividend Reinvestment Plan			17
Plan of Distribution			17
Description of Shares			20
Rights Offerings			23
Certain Provisions in the Declaration of Trust and By-Laws			24
Repurchase of Fund Shares; Conversion to Open-End Fund			26
Tax Matters			27
Custodian and Transfer Agent			29
Independent Registered Public Accounting Firm			29
Legal Matters			29
Available Information			29
Incorporation By Reference			30

You should rely only on the information contained or incorporated by reference into this prospectus supplement and the accompanying prospectus. The Fund has not authorized anyone to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. The Fund is not making an offer of Common Shares in any state where the offer is not permitted. You should not assume that the information contained in this prospectus supplement and the accompanying prospectus is accurate as of any date other than the respective dates on the front covers. The Fund's business, financial condition and prospects may have changed since that date.

FORWARD-LOOKING STATEMENTS

Any projections, forecasts and estimates contained or incorporated by reference herein are forward looking statements and are based upon certain assumptions. Projections, forecasts and estimates are necessarily speculative in nature, and it can be expected that some or all of the assumptions underlying any projections, forecasts or estimates will not materialize or will vary significantly from actual results. Actual results may vary from any projections, forecasts and estimates and the variations may be material. Some important factors that could cause actual results to differ materially from those in any forward-looking statements include changes in interest rates, market, financial or legal uncertainties, including changes in tax law, and the timing and frequency of defaults on underlying investments. Consequently, the inclusion of any projections, forecasts and estimates herein should not be regarded as a representation by the Fund or any of its affiliates or any other person or entity of the results that will actually be achieved by the Fund. Neither the Fund nor its affiliates has any obligation to update or otherwise revise any projections, forecasts and estimates including any revisions to reflect changes in economic conditions or other circumstances arising after the date hereof or to reflect the occurrence of unanticipated events, even if the underlying assumptions do not come to fruition. The Fund acknowledges that, notwithstanding the foregoing, the safe harbor for forward-looking statements under the Private Securities Litigation Reform Act of 1995 does not apply to investment companies such as the Fund.

PROSPECTUS SUPPLEMENT SUMMARY

This is only a summary. You should review the more detailed information contained elsewhere in this prospectus supplement ("Prospectus Supplement"), in the accompanying prospectus and in the statement of additional information ("SAI").

The Fund	Nuveen Municipal High Income Opportunity Fund (the "Fund") is a diversified, closed-end management investment company. The Fund's common shares, $0.01 par value per share (the "Common Shares"), are traded on the NYSE under the symbol "NMZ." See "Description of Shares-Common Shares" in the accompanying prospectus.
Investment Adviser	Nuveen Fund Advisors, LLC ("Nuveen Fund Advisors") is the Fund's investment adviser, responsible for overseeing the Fund's overall investment strategy and its implementation.
	Nuveen Fund Advisors, a registered investment adviser, offers advisory and investment management services to a broad range of investment company clients. Nuveen Fund Advisors has overall responsibility for management of the Fund, oversees the management of the Fund's portfolio, manages the Fund's business affairs and provides certain clerical, bookkeeping and other administrative services. Nuveen Fund Advisors is located at 333 West Wacker Drive, Chicago, Illinois 60606. Nuveen Fund Advisors is an indirect subsidiary of Nuveen, LLC ("Nuveen"), the investment management arm of Teachers Insurance and Annuity Association of America ("TIAA"). TIAA is a life insurance company founded in 1918 by the Carnegie Foundation for the Advancement of Teaching and is the companion organization of College Retirement Equities Fund. As of September 30, 2026, Nuveen managed approximately $1.4 trillion in assets, of which approximately $160.6 billion was managed by Nuveen Fund Advisors.
Sub-Adviser	Nuveen Asset Management, LLC ("Nuveen Asset Management"), located at 333 West Wacker Drive, Chicago, Illinois 60606, serves as the Fund's investment sub-adviser and is an affiliate of Nuveen Fund Advisors. Nuveen Asset Management is a registered investment adviser. Nuveen Asset Management oversees the day-to-day investment operations of the Fund.
Purpose of the Rights Offering	The Board of Trustees of the Fund (the "Board"), based on the recommendations and presentations of Nuveen Fund Advisors, has determined that it is in the best interests of the Fund and holders of its Common Shares (the "Common Shareholders") to conduct this offering of transferable subscription rights ("Rights," and each, a "Right"), thereby increasing the assets of the Fund available for investment.
	Nuveen Fund Advisors believes that a variety of factors indicate that there may be opportunities to make new, attractive investments. Nuveen Fund Advisors expects that the Rights offering will provide an opportunity to increase the assets of the Fund available for investment, thereby better enabling the Fund to take advantage more fully of existing and future investment opportunities that may be or may become available, consistent with the Fund's investment objectives to provide a high level of current income exempt from regular U.S. federal income tax and to seek total return. Nuveen Fund Advisors believes that the Fund may benefit from increased yields, enhanced earnings, tax efficiency and lower expenses.

Terms of the Rights Offering	One Right will be issued for each Common Share held on the Record Date (as defined below). Rights are expected to trade on the NYSE under the symbol "NMZ RT." The Rights will allow Common Shareholders to subscribe for new Common Shares of the Fund. Six Rights will be required to purchase one Common Share (1 for 6). Upon exercise of the Rights offering, Common Shares may be issued at a price below net asset value ("NAV") per Common Share. 217,525,902 Common Shares of the Fund are outstanding as of October 16, 2026. If all Rights in the Primary Subscription are exercised, up to 37,000,000 Common Shares of the Fund could be issued. The actual number of Common Shares issued will be based upon the total number of Common Shares outstanding as of the Record Date, which will be impacted by certain events, such as the issuance of new Common Shares pursuant to the Fund's dividend reinvestment plan or the Fund's current at-the-market offering of Common Shares. See "Description of the Rights Offering-Terms of the Rights Offering." Fractional shares will not be issued upon exercise of Rights. Accordingly, Common Shares may be purchased only pursuant to the exercise of Rights in integral multiples of six. The number of Rights issued to a Record Date Shareholder will be rounded up to the nearest number of Rights evenly divisible by six. An over-subscription privilege will be offered to Record Date Shareholders who fully exercise all Rights initially issued to them to buy those Common Shares that were not purchased by other Rights holders at the same Subscription Price (as defined below), subject to the right of the Board to eliminate the over-subscription privilege (the "Primary Over-Subscription Privilege"). Common Shares issued pursuant to the Primary Over-Subscription Privilege are referred to as "Primary Over-Subscription Shares." Further, if the number of Common Shares requested by Record Date Shareholders exceeds the amount of Common Shares available in the Primary Subscription, the Fund may, subject to the approval of the Board, determine to issue additional Common Shares in an amount of up to 25% of the number of Common Shares issued pursuant to the Primary Subscription (the "Secondary Over-Subscription Privilege"). This amounts to up to an additional 9,250,000 Common Shares, for an aggregate total of up to 46,250,000 Common Shares. Common Shares issued pursuant to the Secondary Over-Subscription Privilege are referred to as the "Secondary Over-Subscription Shares," and together with the Primary Over-Subscription Shares are referred to as the "Over-Subscription Shares." Should the Fund determine to issue any Secondary Over-Subscription Shares, such Secondary Over-Subscription Shares will be allocated only among Record Date Shareholders who submitted requests for Over-Subscription Shares on their Subscription Certificate (as defined below). Over-Subscription Shares will be allocated pro rata among those fully exercising Record Date Shareholders who over-subscribe based on the number of Rights originally issued to them by the Fund.
	The Fund expects to declare monthly distributions payable on December 1, 2026 and December 31, 2026, with record dates of November 13, 2026 and December 2, 2026, respectively. Any Common Shares issued after such record dates as a result of the Rights offering will not be record date Common Shares for the Fund's monthly distributions to be paid on December 1, 2026 and December 31, 2026 and will not be entitled to receive such distributions.
	Rights may be evidenced by subscription certificates or may be uncertificated and evidenced by other appropriate documentation (i.e., a rights card distributed to registered shareholders in lieu of a subscription certificate) (each, a "Subscription Certificate").
	The exercise of Rights by a Rights holder is irrevocable.

Subscription Price	The subscription price per Common Share (the "Subscription Price") will be determined based upon a formula equal to 95% of the average of the last reported sales price of the Common Shares on the NYSE on the Expiration Date (as defined below) and each of the four (4) preceding trading days (the "Formula Price"). If, however, the Formula Price is less than 90% of the NAV per Common Share at the close of trading on the NYSE on the Expiration Date, then the Subscription Price will be 90% of the Fund's NAV per Common Share at the close of trading on the NYSE on the Expiration Date. The Rights offering will expire at 5:00 p.m., Eastern Time, on December 2, 2026 (the "Expiration Date").
Record Date	Rights will be issued to Common Shareholders of record as of the close of business on November 2, 2026 (the "Record Date"). See "Description of the Rights Offering-Terms of the Rights Offering."
Primary and Secondary Over-Subscription Privilege	Common Shareholders as of the close of business on the Record Date who fully exercise all Rights initially issued to them are entitled to buy Primary Over-Subscription Shares. If enough Primary Over-Subscription Shares are available, all such requests will be honored in full. If the requests for Primary Over-Subscription Shares exceed the Primary Over-Subscription Shares available, the available Primary Over-Subscription Shares will be allocated pro rata among those fully exercising Record Date Shareholders who over-subscribe based on the number of Rights originally issued to them by the Fund. Common Shares acquired pursuant to the Primary Over-Subscription Privilege are subject to allotment. Rights acquired in the secondary market may not participate in the Primary Over-Subscription Privilege. Further, if the number of Common Shares requested by Record Date Shareholders exceeds the amount of Common Shares available in the Primary Subscription, the Fund may, subject to the approval of the Board, elect to issue up to an additional 25% of the amount of Common Shares offered in the Primary Subscription through a Secondary Over-Subscription Privilege. The Secondary Over-Subscription Shares will be allocated only among Record Date Shareholders who requested Over-Subscription Shares as part of the Primary Subscription. To the extent a sufficient amount of Common Shares are not available to fulfill all over-subscription requests, Common Shares will be allocated pro rata among those Record Date Shareholders who over-subscribe based on the number of Rights originally issued to them by the Fund. Like Primary Over-Subscription Shares, Secondary Over-Subscription Shares are subject to allotment. Rights acquired in the secondary market may not participate in the Secondary Over-Subscription Privilege. Notwithstanding the above, the Board has the right in its absolute discretion to eliminate the Primary Over-Subscription Privilege if it considers it to be in the best interest of the Fund to do so. The Board may make that determination at any time, without prior notice to Rights holders or others, up to and including the fifth day following the Expiration Date. See "Description of the Rights Offering-Primary and Secondary Over-Subscription Privilege." Common Shareholders who choose not to exercise their full Rights to purchase additional Common Shares will permit Common Shareholders who exercise an over-subscription privilege to purchase additional Common Shares at a discount to NAV without furnishing additional Rights or providing any compensation to the non-participating Common Shareholders for the dilution of their ownership percentage or voting rights. Any Common Shares issued pursuant to an over-subscription privilege will be shares registered under the Prospectus.

Transfer of Rights	The Rights will be transferable. See "Description of the Rights Offering-Terms of the Rights Offering," "Sale of Rights" and "Method of Transferring Rights."
Title	Subscription Rights to Acquire Common Shares.
Subscription Period	The Rights may be exercised at any time after issuance and prior to expiration of the Rights (the "Subscription Period"), which will be 5:00 p.m., Eastern Time, on December 2, 2026 (the "Expiration Date"), unless otherwise extended. See "Description of the Rights Offering-Terms of the Rights Offering" and "-Method of Exercise of Rights." The Rights offering may be terminated or extended by the Fund at any time for any reason before 5:00 p.m., Eastern Time, on the Expiration Date. If the Fund terminates the Rights offering, the Fund will issue a press release announcing such termination and will direct the Subscription Agent (defined below) to return, without interest, all subscription proceeds received to such shareholders who had elected to purchase Common Shares.
Offering Expenses	The expenses of the Rights offering are expected to be approximately $371,000 and will be borne by Nuveen Fund Advisors, and not the Fund or Common Shareholders. See "Use of Proceeds."
Sale of Rights	The Rights are transferable until the completion of the Subscription Period and will be admitted for trading on the NYSE under the symbol "NMZ RT." Although no assurance can be given that a market for the Rights will develop or be maintained, trading in the Rights on the NYSE is expected to begin on October 30, 2026, one Business Day prior to the Record Date, and may be conducted until the close of trading on the last NYSE trading day prior to the Expiration Date. For purposes of this Prospectus Supplement, a "Business Day" shall mean any day on which trading is conducted on the NYSE. See "Description of the Rights Offering - Terms of the Rights Offering" for more information. The value of the Rights, if any, will be reflected by their market price on the NYSE. Rights may be sold by individual holders through their broker or financial advisor or may be submitted to the Subscription Agent (defined below) for sale. Any Rights submitted to the Subscription Agent for sale must be received by the Subscription Agent prior to 5:00 p.m., Eastern Time, on or before November 24, 2026, five Business Days prior to the Expiration Date (or, if the Subscription Period is extended, prior to 5:00 p.m., Eastern Time, on the fifth Business Day prior to the extended Expiration Date). Rights that are sold will not confer any right to acquire any Common Shares in any over-subscription, and any Record Date Shareholder who sells any Rights will not be eligible to participate in the over-subscription privilege, if any. Trading of the Rights on the NYSE will be conducted on a when-issued basis until and including the date on which the Subscription Certificates (as defined below) are mailed to Record Date Shareholders and thereafter will be conducted on a regular-way basis until and including the last NYSE trading day prior to the completion of the Subscription Period. The Common Shares are expected to begin trading ex-Rights on the Record Date. If the Subscription Agent receives Rights for sale in a timely manner, the Subscription Agent will use its best efforts to sell the Rights on the NYSE. The Subscription Agent will also attempt to sell any Rights attributable to shareholders of record whose addresses are outside the United States, or who have an APO or FPO address. See "Description of the Rights Offering-Foreign Restrictions." The Subscription Agent will attempt to sell such Rights on the NYSE.
	Any commissions will be paid by the selling Rights holders. Neither the Fund nor the Subscription Agent will be responsible if Rights cannot be sold and neither has guaranteed any minimum sales price for the Rights. If the Rights can be sold, sales of these Rights will be deemed to have been effected at the weighted average price received by the Subscription Agent on the day such Rights are sold, less any applicable brokerage commissions, taxes and other expenses (i.e., costs incidental to the sale of Rights).

	Common Shareholders are urged to obtain a recent trading price for the Rights on the NYSE from their broker, bank, financial advisor or the financial press.
	Banks, broker-dealers and trust companies that hold shares for the accounts of others are advised to notify those persons that purchase Rights in the secondary market that such Rights will not participate in any over-subscription privilege. See "Description of the Rights Offering-Terms of the Rights Offering."
Use of Proceeds	The Fund estimates the net proceeds of the Rights offering to be approximately $318,200,000. This figure is based on the estimated Subscription Price per Common Share of $8.60 (95% of the average of the last reported sales price of the Fund's Common Shares on the NYSE on October 16, 2026 and each of the four (4) preceding trading days) and assumes all new Common Shares offered are sold and that the expenses related to the Rights offering estimated at approximately $371,000 are paid by Nuveen Fund Advisors. The Fund intends to invest the net proceeds from the issuance of Rights hereunder in accordance with the Fund's investment objectives and policies as set forth in the accompanying prospectus. The Fund currently anticipates that it will be able to invest substantially all of the net proceeds in investments that meet the Fund's investment objectives and policies within approximately three months of the receipt of such proceeds; however, the identification of appropriate investment opportunities pursuant to the Fund's investment style or changes in market conditions may cause the investment period to extend as long as six months (the "invest-up period"). Pending investment, it is anticipated that the proceeds will be invested in short-term or long-term securities issued by the U.S. Government and its agencies or instrumentalities or in high-quality, short-term money market instruments. In addition, the Fund may use such proceeds to pay distributions to shareholders. Current market conditions may change and the Fund may not be able to invest the proceeds as planned. Immediately after the initial invest-up period, the Fund's portfolio allocations may vary over time consistent with the Fund's investment policies as described in the accompanying prospectus. Depending on market conditions and operations, a portion of the cash held by the Fund, including any proceeds raised from the offering, may be used to pay distributions in accordance with the Fund's distribution policy and may be a return of capital. A return of capital is a return to investors of a portion of their original investment in the Fund. In general terms, a return of capital would involve a situation in which a Fund distribution (or a portion thereof) represents a return of a portion of a shareholder's investment in the Fund, rather than making a distribution that is funded from the Fund's earned income or other profits. Although return of capital distributions may not be currently taxable, such distributions would decrease the basis of a shareholder's shares, and therefore, may increase a shareholder's tax liability for capital gains upon a sale of shares, even if sold at a loss to the shareholder's original investments. See "Use of Proceeds."
Taxation/ERISA	See "Taxation" and "Description of the Rights Offering-Employee Benefit Plan and IRA Considerations."
Subscription Agent	Computershare Trust Company, N.A. and Computershare Inc. See "Description of the Rights Offering-Subscription Agent."
Information Agent	Georgeson LLC. See "Description of the Rights Offering-Information Agent."

Risk Factors

See "Risk Factors" in the accompanying prospectus and "Special Characteristics and Risks of the Rights Offering" in this Prospectus Supplement for a discussion of the principal risks you should carefully consider before deciding to invest in Common Shares through Rights.

DESCRIPTION OF THE RIGHTS OFFERING

Purpose of the Rights Offering

The Board, based on the recommendations and presentations of Nuveen Fund Advisors, has determined that it is in best interests of the Fund and its Common Shareholders to conduct the Rights offering, thereby increasing the assets of the Fund available for investment. In making this determination, the Board considered a number of factors, including potential benefits and costs. In particular, the Board considered Nuveen Fund Advisors' opinion that the Rights offering would better enable the Fund to take advantage more fully of existing and future investment opportunities that may be or may become available, consistent with the Fund's investment objectives.

In making its determination that the Rights offering would result in a net benefit to existing Common Shareholders of the Fund, the Board considered various factors at its meeting held on October 22, 2026, including the advice and recommendations of Nuveen Fund Advisors. The factors considered by the Board included: (i) the size of the Rights offering (including the number of Rights needed to purchase one Common Share and size of the Rights offering in relation to the number of Common Shares outstanding), Subscription Price, pricing (including the pricing formula, as compared to a fixed price, and reasons for selecting the formula) and structure of the Rights offering (including the possible negative effect of the Rights offering on the market price of Common Shares), which will not discriminate among shareholders; (ii) the expected lowering of the Fund's ongoing operating expenses as a proportion of net assets due to the increase in Fund assets as a result of the Rights offering because the Fund's fixed costs would be spread over a larger asset base; (iii) the Rights offering, if it is well-subscribed, which would result in a larger number of outstanding Common Shares and a potentially larger number of beneficial owners of Common Shares, could increase the level of market interest in and visibility of the Fund and improve the trading liquidity of the Common Shares on the NYSE; (iv) the opportunity the Rights offering represents for current Common Shareholders to purchase additional Common Shares at a discount to market price and NAV; (v) Nuveen Fund Advisors' opinion that raising additional capital through a Rights offering would allow the Fund to better capitalize on attractive investment opportunities without having to sell existing positions and that the new investments should be able to help sustain the Fund's current distribution over the longer term; (vi) the size of the current premium to NAV at which the Common Shares are trading and the potential impact of the Rights offering on the market price and premium to NAV of the Common Shares; (vii) the extent of dilution for: (a) participating Common Shareholders, and (b) non-participating Common Shareholders; (viii) the benefits and drawbacks of conducting a non-transferable versus a transferable rights offering and Nuveen Fund Advisors' commitment to use its best efforts to ensure an adequate trading market will exist for the Rights; (ix) the expenses of the Rights offering and Nuveen Fund Advisors' commitment to bear all costs of the Rights offering, which would reduce the effects of any dilution as a result of the Rights offering; and (x) the effect on the Fund and its existing Common Shareholders if the Rights offering is not fully subscribed and, conversely, if the Rights offering is oversubscribed. The Board also considered that increasing the Fund's assets results in a benefit to Nuveen Fund Advisors because the management fee paid by the Fund to Nuveen Fund Advisors increases as the Fund's Managed Assets increase (including from the expected commensurate increase in the Fund's use of leverage).

Nuveen Fund Advisors believes that a variety of factors indicate that there may be opportunities to make new, attractive investments for the Fund. Nuveen Fund Advisors expects that the Rights offering will provide an opportunity to increase the assets of the Fund available for investment. Nuveen Fund Advisors believes that the Fund may benefit from increased yields, enhanced earnings, tax efficiency and lower expenses. Nuveen Fund Advisors has an inherent conflict of interest in recommending the Rights offering because the Fund pays fees to Nuveen Fund Advisors based on a percentage of the Fund's Managed Assets (the greater the Managed Assets of the Fund, the greater the compensation paid to Nuveen Fund Advisors). "Managed Assets" means the total value of the assets of the Fund, minus the sum of its accrued liabilities (other than Fund liabilities incurred for the express purpose of creating leverage). Total assets for this purpose shall include assets attributable to the Fund's use of leverage (whether or not those assets are reflected in the Fund's financial statements for purposes of generally accepted accounting principles).

The Rights offering seeks to provide an opportunity to existing Common Shareholders to purchase Common Shares at a discount to market price and NAV. The issuance to Common Shareholders of transferable Rights, which may themselves have intrinsic value, also will afford non-participating Common Shareholders of record on the Record Date, the potential of receiving cash payment upon the sale of the Rights, receipt of which may be viewed as partial compensation for dilution of their interests that will occur as a result of the Rights offering. There can be no assurance that a market for the Rights will develop or, if such a market does develop, that such market will be maintained or what the price of the Rights will be.

Terms of the Rights Offering

The Fund is issuing to Record Date Shareholders Rights to subscribe for Common Shares of the Fund. Each Record Date Shareholder is being issued one transferable Right for each Common Share owned on the Record Date. The Rights entitle the holder to acquire one new Common Share for every six Rights held (1 for 6) (provided that any Record Date Shareholder who owns fewer than six Common Shares as of the close of business on the Record Date may subscribe for one full Common Share), at a Subscription Price per Common Share determined based upon a formula equal to 95% of the average of the last reported sales price of the Common Shares on the NYSE on the Expiration Date, as such date may be extended from time to time, and each of the four (4) preceding trading days (the "Formula Price"). If, however, the Formula Price is less than 90% of the NAV per Common Share at the close of trading on the NYSE on the Expiration Date, then the Subscription Price will be 90% of the Fund's NAV per Common Share at the close of trading on the NYSE on the Expiration Date.

The estimated Subscription Price to the public of $8.60 is based upon 95% of the average of the last reported sales price of the Common Shares on the NYSE on October 16, 2026 and each of the four (4) preceding trading days. Fractional shares will not be issued upon exercise of Rights. Accordingly, Common Shares may be purchased only pursuant to the exercise of Rights in integral multiples of six. The number of Rights issued to a Record Date Shareholder will be rounded up to the nearest number of Rights evenly divisible by six. Rights may be exercised at any time during the period (the "Subscription Period") which commences on November 2, 2026, and ends at 5:00 p.m., Eastern Time, on December 2, 2026 (the "Expiration Date"), unless otherwise extended. Upon exercise of the Rights offering, Common Shares may be issued at a price below NAV per Common Share. The right to acquire one Common Share for each six Rights held during the Subscription Period (or any extension of the Subscription Period) at the Subscription Price will be referred to in the remainder of this Prospectus Supplement as the "Rights offering." Rights will expire on the Expiration Date and all unexercised rights at that time will become void and may not be exercised unless the Expiration Date is extended as described herein.

The Fund expects to declare monthly distributions payable on December 1, 2026 and December 31, 2026, with record dates of November 13, 2026 and December 2, 2026, respectively. Any Common Shares issued after such record dates as a result of the Rights offering will not be record date Common Shares for the Fund's monthly distributions to be paid on December 1, 2026 and December 31, 2026 and will not be entitled to receive such distributions.

Rights may be evidenced by subscription certificates or may be uncertificated and evidenced by other appropriate documentation (i.e., a rights card distributed to registered shareholders in lieu of a subscription certificate) ("Subscription Certificates"). The number of Rights issued to each holder will be stated on the Subscription Certificate delivered to the holder. The method by which Rights may be exercised and Common Shares paid for is set forth below in "Method of Exercise of Rights" and "Payment for Shares." A holder of Rights will have no right to rescind a purchase after Computershare Trust Company, N.A. and Computershare Inc. (together, the "Subscription Agent") has received payment. See "Payment for Shares" below. It is anticipated that the Common Shares issued pursuant to an exercise of Rights will be listed on the NYSE.

Holders of Rights who are Record Date Shareholders are entitled to over-subscribe for additional Common Shares at the same Subscription Price pursuant to the Primary Over-Subscription Privilege, subject to certain limitations, allotment and the right of the Board to eliminate the Primary Over-Subscription Privilege.

In addition, if the number of Common Shares requested by Record Date Shareholders exceeds the amount of Common Shares available in the Primary Subscription, the Fund may, subject to the approval of the Board, elect to issue additional Common Shares in an amount of up to 25% of the number of Common Shares issued as part of the Primary Subscription. Should the Fund determine to issue some or all of the Secondary Over-Subscription Shares, they will be allocated only among Record Date Shareholders who requested Over-Subscription Shares on their Subscription Certificate. Secondary Over-Subscription Shares will be allocated pro rata among those fully exercising Record Date Shareholders who over-subscribe based on the number of Rights originally issued to them by the Fund.

The entitlement to subscribe for any Over-Subscription Shares is available only to those Record Date Shareholders who fully exercise all Rights initially issued to them and only on the basis of their Record Date holdings. See below under "Description of the Rights Offering-Primary and Secondary Over-Subscription Privileges" below.

For purposes of determining the maximum number of Common Shares that may be acquired pursuant to the Rights offering, broker-dealers, trust companies, banks or others whose shares are held of record by Cede & Co. ("Cede"), as nominee for the Depository Trust Company ("DTC"), or by any other depository or nominee will be deemed to be the holders of the Rights that are held by Cede or such other depository or nominee on their behalf.

The Rights are transferable until the completion of the Subscription Period and will be admitted for trading on the NYSE under the symbol "NMZ RT." Assuming a market exists for the Rights, the Rights may be purchased and sold through usual brokerage channels and also sold through the Subscription Agent. Although no assurance can be given that a market for the Rights will develop or be maintained, trading in the Rights on the NYSE is expected to begin on October 30, 2026, one Business Day prior to the Record Date, and may be conducted until the close of trading on the last NYSE trading day prior to the Expiration Date. Trading of the Rights on the NYSE is expected to be conducted initially on a when-issued basis under the symbol "NMZ RTWI" on October 30, 2026 until and including the date on which the Subscription Certificates are mailed to Record Date Shareholders of record and thereafter is expected to be conducted on a regular way basis under the symbol "NMZ RT" until and including the last NYSE trading day prior to the Expiration Date. The method by which Rights may be transferred is set forth below under "Method of Transferring Rights." The Common Shares are expected to begin trading ex-Rights on the Record Date as determined and announced by the NYSE. The Rights offering may be terminated or extended by the Fund at any time for any reason before 5:00 p.m., Eastern Time, on the Expiration Date. If the Fund terminates the Rights offering, the Fund will issue a press release announcing such termination and will direct the Subscription Agent to return, without interest, all subscription proceeds received to such shareholders who had elected to purchase Common Shares.

Nominees who hold Common Shares for the account of others, such as banks, broker-dealers, trustees or depositories for securities, should notify the respective beneficial owners of such shares as soon as possible to ascertain such beneficial owners' intentions and to obtain instructions with respect to the Rights. If the beneficial owner so instructs, the nominee should complete the Subscription Certificate and submit it to the Subscription Agent with proper payment. In addition, beneficial owners of the Common Shares or Rights held through such a nominee should contact the nominee and request the nominee to effect transactions in accordance with such beneficial owner's instructions.

Participants in the Fund's Dividend Reinvestment Plan (the "Plan") will be issued Rights in respect of the Common Shares held in their accounts in the Plan. Participants wishing to exercise these Rights must exercise the Rights in accordance with the procedures set forth in "Method of Exercise of Rights" and "Payment for Shares."

Conditions of the Rights Offering

The Rights offering is being made in accordance with the Investment Company Act of 1940, as amended (the "1940 Act"), without shareholder approval. The staff of the SEC has interpreted the 1940 Act as not requiring shareholder approval of a transferable rights offering to purchase common shares at a price below the then current NAV so long as certain conditions are met, including: (i) the Board makes a good faith determination that such offering would result in a net benefit to existing shareholders; (ii) the offering fully protects shareholders' preemptive rights and does not discriminate among shareholders (except for the possible effect of not offering fractional rights); (iii) management uses its best efforts to ensure an adequate trading market in the Rights for use by shareholders who do not exercise such Rights; and (iv) the ratio of such transferable Rights offering does not exceed one new share for each three rights held.

Important Dates to Remember

Please note that the dates in the table below may change if the Rights offering is extended.

Event		Date
Record Date		November 2, 2026
Subscription Period		November 2, 2026 through December 2, 2026†
Final Day Rights Will Trade		December 1, 2026†
Expiration Date*		December 2, 2026†
Notice of Guaranteed Delivery Due*		December 2, 2026†
Guarantee Expiration Date		December 3, 2026†
Issuance Date		December 9, 2026†
Confirmation Date		December 14, 2026†

*

A shareholder exercising Rights must deliver to the Subscription Agent by 5:00 p.m., Eastern Time, on December 2, 2026 (unless the Rights offering is extended) either (a) a Subscription Certificate and payment for Common Shares or (b) a notice of guaranteed delivery and payment for Common Shares.

†

Unless the Rights offering is extended.

Primary and Secondary Over-Subscription Privilege

Record Date Shareholders who fully exercise their Rights are entitled to subscribe for additional Common Shares at the same Subscription Price pursuant to the Primary and Secondary Over-Subscription Privilege, subject to certain limitations and subject to allotment. The Board has the right in its absolute discretion to eliminate the Primary Over-Subscription Privilege if it considers it to be in the best interest of the Fund to do so. The Board may make that determination at any time, without prior notice to Rights holders or others, up to and including the fifth day following the Expiration Date. If the Primary Over-Subscription Privilege is exercised, it will operate as set forth below.

Record Date Shareholders who fully exercise all Rights initially issued to them are entitled to buy those Common Shares, referred to as Primary Over-Subscription Shares, that were not purchased by other holders of Rights at the same Subscription Price. If enough Primary Over-Subscription Shares are available, all such requests will be honored in full. Common Shares acquired pursuant to the Primary Over-Subscription Privilege are subject to allotment.

If the number of Common Shares requested by Record Date Shareholders exceeds the amount of Common Shares available in the Primary Subscription, the Fund may, subject to the approval of the Board, elect to issue Secondary Over-Subscription Shares in an amount of up to 25% of the number of Common Shares issued pursuant to the Primary Subscription. Should the Fund determine to issue some or all of the Secondary Over-Subscription Shares, they will be allocated only among Record Date Shareholders who requested Over-Subscription Shares on their Subscription Certificate. Common Shares acquired pursuant to the Secondary Over-Subscription Privilege are subject to allotment.

Record Date Shareholders who are fully exercising their Rights during the Subscription Period should indicate on the Subscription Certificate that they submit with respect to the exercise of the Rights issued to them, how many Common Shares they are willing to acquire pursuant to any Primary Over-Subscription Privilege and Secondary Over-Subscription Privilege. Rights acquired in the secondary market may not participate in any Primary Over-Subscription Privilege or Secondary Over-Subscription Privilege.

To the extent sufficient Common Shares are not available to fulfill all over-subscription requests, the Over-Subscription Shares will be allocated pro rata among those Record Date Shareholders who over-subscribe based on the number of Rights issued to them by the Fund. The allocation process may involve a series of allocations in order to assure that the total number of Common Shares available for over-subscriptions is distributed on a pro rata basis.

The formula to be used in allocating the Over-Subscription Shares is as follows:

Shareholder's Record Date Position		X		Over-Subscription
Total Record Date Position of All Over-Subscribers				Shares Remaining

Banks, broker-dealers, trustees and other nominee holders of Rights will be required to certify to the Subscription Agent, before any over-subscription privilege may be exercised with respect to any particular beneficial owner, as to the aggregate number of Rights exercised during the Subscription Period and the number of Common Shares subscribed for pursuant to the over-subscription privilege by such beneficial owner and that such beneficial owner's subscription was exercised in full. Nominee holder over-subscription forms and beneficial owner certification forms will be distributed to banks, broker-dealers, trustees and other nominee holders of Rights with the Subscription Certificates. Nominees should also notify holders purchasing Rights in the secondary market that such Rights may not participate in any over-subscription privilege.

Common Shareholders who choose not to exercise their full rights to purchase additional Common Shares will permit Common Shareholders who exercise an over-subscription privilege to purchase additional Common Shares at a discount to NAV without furnishing additional Rights or providing any compensation to the non-participating Common Shareholders for the dilution of their ownership percentage or voting rights.

The Fund will not otherwise offer or sell any Common Shares that are not subscribed for pursuant to the Primary Subscription or over-subscription privileges pursuant to the Rights offering.

Sale of Rights

The Rights are transferable and will be admitted for trading on the NYSE under the symbol "NMZ RT." Although no assurance can be given that a market for the Rights will develop or be maintained, trading in the Rights on the NYSE is expected to begin on October 30, 2026, one Business Day prior to the Record Date, and may be conducted until the close of trading on the last NYSE trading day prior to the Expiration Date. See "Description of the Rights Offering - Terms of the Rights Offering" for more information.

The value of the Rights, if any, will be reflected by the market price. Rights may be sold by individual holders through their broker or other financial intermediary. Holders of Rights attempting to sell any unexercised Rights in the open market through their broker or financial advisor may be charged a commission or incur other transaction expenses and should consider the commissions and fees charged prior to selling their Rights on the open market.

Rights that are sold will not confer any right to acquire any Common Shares in any Primary or Secondary Over-Subscription Privilege, if any, and any Record Date Shareholder who sells any Rights will not be eligible to participate in any Primary or Secondary Over-Subscription Privilege.

Trading of the Rights on the NYSE will be conducted on a when-issued basis until and including the date on which the Subscription Certificates are mailed to Record Date Shareholders of record and thereafter will be conducted on a regular-way basis until and including the last NYSE trading day prior to the Expiration Date. The Common Shares are expected to begin trading ex-Rights on the Record Date.

Shareholders are urged to obtain a recent trading price for the Rights on the NYSE from their broker, bank, financial advisor or the financial press.

Holders of Rights who are unable or do not wish to exercise any or all of their Rights may contact the Information Agent if they have questions about the sale of any unexercised Rights. Rights holders who hold their shares through a broker-dealer or other applicable financial intermediary should contact their broker-dealer or other applicable financial intermediary if they wish to sell their Rights. Shareholders of record whose addresses are outside the United States, or who have an APO or FPO address, are encouraged to contact the Information Agent if they want to exercise their Rights. If an instruction to exercise their Rights is not received within five business days of the Expiration Date, their Rights will be sold. The selling Rights holder will pay all applicable brokerage commissions incurred. There can be no assurance that the Subscription Agent will be able to facilitate the sale of any of Rights and neither the Fund nor the Subscription Agent has guaranteed any minimum sales price for the Rights.

Method of Transferring Rights

The Rights evidenced by a single Subscription Certificate may be transferred in whole by endorsing the Subscription Certificate for transfer in accordance with the accompanying instructions. A portion of the Rights evidenced by a single Subscription Certificate (but not fractional Rights) may be transferred by delivering to the Subscription Agent a Subscription Certificate properly endorsed for transfer, with instructions to register the portion of the Rights evidenced thereby in the name of the transferee (and to issue a new Subscription Certificate to the transferee evidencing the transferred Rights). In this event, a new Subscription Certificate evidencing the balance of the Rights will be issued to the Rights holder or, if the Rights holder so instructs, to an additional transferee.

Holders wishing to transfer all or a portion of their Rights (but not fractional Rights) should promptly transfer such Rights to ensure that: (i) the transfer instructions will be received and processed by the Subscription Agent, (ii) a new Subscription Certificate will be issued and transmitted to the transferee or transferees with respect to transferred Rights, and to the holder with respect to retained Rights, if any, and (iii) the Rights evidenced by the new Subscription Certificates may be exercised or sold by the recipients thereof prior to the Expiration Date. Neither the Fund nor the Subscription Agent shall have any liability to a transferee or holder of Rights if Subscription Certificates are not received in time for exercise or sale prior to the Expiration Date.

Except for the fees charged by the Subscription Agent (which will be paid by Nuveen Fund Advisors as described below), all commissions, fees and other expenses (including brokerage commissions and transfer taxes) incurred in connection with the purchase, sale, transfer or exercise of Rights will be for the account of the holder of the Rights, and none of these commissions, fees or expenses will be borne by the Fund or the Subscription Agent.

The Fund anticipates that the Rights will be eligible for transfer through, and that the exercise of the Rights may be effected through, the facilities of DTC (Rights exercised through DTC are referred to as "DTC Exercised Rights").

Subscription Agent

The Subscription Agent is Computershare Trust Company, N.A. and Computershare Inc. The Subscription Agent will receive an amount estimated to be $80,000, comprised of the fee for its services and the reimbursement for certain expenses related to the Rights offering. Nuveen Fund Advisors, not the Fund or Common Shareholders, will pay such amount.

Information Agent

INQUIRIES BY ALL HOLDERS OF RIGHTS SHOULD BE DIRECTED TO: THE INFORMATION AGENT, GEORGESON LLC. BANKS, BROKERS AND SHAREHOLDERS PLEASE CALL TOLL-FREE AT 888-745-9838.

Method of Exercise of Rights

Rights may be exercised by completing and signing the Subscription Certificate and delivering the completed and signed Subscription Certificate to the Subscription Agent, together with payment for the Common Shares as described below under "Payment for Shares." Rights may also be exercised through the broker of a holder of Rights, who may charge the holder of Rights a servicing fee in connection with such exercise.

Completed Subscription Certificates and payment must be received by the Subscription Agent prior to 5:00 p.m., Eastern Time, on the Expiration Date (unless payment is effected by means of a notice of guaranteed delivery as described below under "Payment for Shares"). Your broker, bank, trust company or other intermediary may impose a deadline for exercising Rights earlier than 5:00 p.m., Eastern Time, on the Expiration Date. The Subscription Certificate and payment should be delivered to the Subscription Agent at the following address:

If By Mail:

Computershare

C/O Voluntary Corporate Actions

P.O. Box 43011

Providence, RI 02940-3011

If By Overnight Courier:

Computershare

C/O Voluntary Corporate Actions

150 Royall Street, Suite V

Canton, MA 02021

If By Notice of Guaranteed Delivery:

email to [email protected]

Contact your broker-dealer, trust company, bank or other nominee to notify the Fund of your intent to exercise, sell or transfer the Rights.

Payment for Shares

Holders of Rights who acquire Common Shares in the Rights offering may choose between the following methods of payment:

(1)

A holder of Rights can send the Subscription Certificate, together with payment in the form of a check (which must include the name of the shareholder on the check) for the Common Shares subscribed for in the Rights offering and, if eligible, for any additional Common Shares subscribed for pursuant to the over-subscription privilege, to the Subscription Agent based on the estimated Subscription Price. To be accepted, the payment, together with the executed Subscription Certificate, must be received by the Subscription Agent at one of the addresses noted above prior to 5:00 p.m., Eastern Time, on the Expiration Date. The Subscription Agent will deposit all share purchase checks received by it prior to the final due date into a segregated account pending proration and distribution of Common Shares. The Subscription Agent will not accept cash as a means of payment for Common Shares.

(2)

Alternatively, a subscription will be accepted by the Subscription Agent if, prior to 5:00 p.m., Eastern Time, on the Expiration Date, the Subscription Agent has received a written notice of guaranteed delivery by mail or email from a bank, trust company, or a NYSE member, guaranteeing delivery of a properly completed and executed Subscription Certificate. In order for the notice of guarantee to be valid, full payment for the Common Shares at the estimated Subscription Price must be received with the notice. The Subscription Agent will not honor a notice of guaranteed delivery unless a properly completed and executed Subscription Certificate is received by the Subscription Agent by the close of business on the first Business Day after the Expiration Date. The notice of guaranteed delivery must be emailed to the Subscription Agent at [email protected] or delivered to the Subscription Agent at one of the addresses noted above.

A PAYMENT PURSUANT TO THIS METHOD MUST BE IN UNITED STATES DOLLARS BY CHECK (WHICH MUST INCLUDE THE NAME OF THE SHAREHOLDER ON THE CHECK) DRAWN ON A BANK LOCATED IN THE UNITED STATES, MUST BE PAYABLE TO NUVEEN Municipal HIGH INCOME OPPORTUNITY FUND AND MUST ACCOMPANY AN EXECUTED SUBSCRIPTION CERTIFICATE TO BE ACCEPTED.

If a holder of Rights who acquires Common Shares pursuant to the subscription makes payment of an insufficient amount, the Fund reserves the right to take any or all of the following actions: (i) reallocate such subscribed and unpaid-for Common Shares to Record Date Shareholders exercising the over-subscription privilege who did not receive the full over-subscription requested; (ii) apply any payment actually received by it toward the purchase of the greatest whole number of Common Shares which could be acquired by such holder upon exercise of the Rights or any over-subscription privilege; and (iii) exercise any and all other rights or remedies to which it may be entitled, including, without limitation, the right to set off against payments actually received by it with respect to such subscribed Common Shares (in other words, retain such payments) and to enforce the exercising Rights holder's relevant payment obligation.

Any payment required from a holder of Rights must be received by the Subscription Agent prior to 5:00 p.m., Eastern Time, on the Expiration Date. Issuance and delivery of the Common Shares purchased are subject to collection of checks.

Within eight Business Days following the Expiration Date (the "Confirmation Date"), a confirmation will be sent by the Subscription Agent to each holder of Rights (or, if the Common Shares are held by Cede or any other depository or nominee, to Cede or such other depository or nominee), showing (i) the number of Common Shares acquired pursuant to the Primary Subscription, (ii) the number of Over-Subscription Shares, if any, acquired pursuant to any over-subscription privilege, and (iii) the per share and total purchase price for the Common Shares. Any additional payment required from a Record Date Shareholder for the difference between the estimated Subscription Price and the actual Subscription Price will be reflected in an invoice to such shareholder. Any excess payment to be refunded by the Fund to a holder of Rights, or to be paid to a holder of Rights as a result of sales of Rights on its behalf by the Subscription Agent, will be mailed by the Subscription Agent to the holder within eight Business Days after the Expiration Date.

A holder of Rights will have no right to rescind a purchase after the Subscription Agent has received payment either by means of a notice of guaranteed delivery or a check, which must include the name of the shareholder on the check.

Upon acceptance of a subscription, all funds received by the Subscription Agent shall be held by the Subscription Agent as agent for the Fund and deposited in one or more bank accounts. Such funds may be invested by the Subscription Agent in bank accounts, short-term certificates of deposit, bank repurchase agreements, and disbursement accounts with commercial banks meeting certain standards. The Subscription Agent may receive interest, dividends or other earnings in connection with such deposits or investments.

Holders, such as broker-dealers, trustees or depositories for securities, who hold Common Shares for the account of others, should notify the respective beneficial owners of the Common Shares as soon as possible to ascertain such beneficial owners' intentions and to obtain instructions with respect to the Rights. If the beneficial owner so instructs, the record holder of the Rights should complete Subscription Certificates and submit them to the Subscription Agent with the proper payment. In addition, beneficial owners of Common Shares or Rights held through such a holder should contact the holder and request that the holder effect transactions in accordance with the beneficial owner's instructions. Banks, broker-dealers, trustees and other nominee holders that hold Common Shares of the Fund for the accounts of others are advised to notify those persons that purchase Rights in the secondary market that such Rights may not participate in any over-subscription privilege offered.

THE INSTRUCTIONS ACCOMPANYING THE SUBSCRIPTION CERTIFICATES SHOULD BE READ CAREFULLY AND FOLLOWED IN DETAIL. DO NOT SEND SUBSCRIPTION CERTIFICATES TO THE FUND.

THE METHOD OF DELIVERY OF SUBSCRIPTION CERTIFICATES AND PAYMENT OF THE ESTIMATED SUBSCRIPTION PRICE TO THE SUBSCRIPTION AGENT WILL BE AT THE ELECTION AND RISK OF THE RIGHTS HOLDERS, BUT IF SENT BY MAIL IT IS RECOMMENDED THAT THE CERTIFICATES AND PAYMENTS BE SENT BY REGISTERED MAIL, PROPERLY INSURED, WITH RETURN RECEIPT REQUESTED, AND THAT A SUFFICIENT NUMBER OF DAYS BE ALLOWED TO ENSURE DELIVERY TO THE SUBSCRIPTION AGENT AND CLEARANCE OF PAYMENT PRIOR TO 5:00 P.M., EASTERN TIME, ON THE EXPIRATION DATE BECAUSE UNCERTIFIED PERSONAL CHECKS MAY TAKE AT LEAST FIVE BUSINESS DAYS TO CLEAR.

All questions concerning the timeliness, validity, form and eligibility of any exercise of Rights will be determined by the Fund, whose determinations will be final and binding. The Fund in its sole discretion may waive any defect or irregularity, or permit a defect or irregularity to be corrected within such time as it may determine, or reject the purported exercise of any Right. Subscriptions will not be deemed to have been received or accepted until all irregularities have been waived or cured within such time as the Fund determines in its sole discretion. Neither the Fund nor the Subscription Agent will be under any duty to give notification of any defect or irregularity in connection with the submission of Subscription Certificates or incur any liability for failure to give such notification.

Foreign Restrictions

Subscription Certificates will only be mailed to Record Date Shareholders whose addresses are within the United States (other than an APO or FPO address). Because the Rights offering will not be registered in any jurisdiction other than the United States, shareholders of record in any jurisdiction outside of the United States should contact the Information Agent for assistance in facilitating the sale of the Rights issued to Record Date Shareholders outside of the United States. The Subscription Agent will attempt to sell all of the Rights issued to shareholders outside these jurisdictions and remit the net proceeds, if any, to such shareholders of record. If the Rights can be sold, sales of these Rights will be deemed to have been effected at the weighted average price received by the Subscription Agent on the day the Rights are sold, less any applicable brokerage commissions, taxes and other expenses.

For beneficial owners of the Fund's Common Shares who hold their Common Shares through a custodian bank, broker, dealer, or other nominee, it is the responsibility of the nominee holder to determine whether the beneficial owner is eligible to participate in the jurisdiction in which they reside, as the nominee holder will submit instructions on behalf of the beneficial owner through DTC.

Employee Benefit Plan and IRA Considerations

Holders of Rights that are employee benefit plans subject to limitations imposed by the Internal Revenue Code of 1986, as amended (the "Code"), such as employee plans subject to the Employee Retirement Income Security Act of 1974, as amended ("ERISA"), Keogh Plans and Individual Retirement Accounts ("IRA") (each a "Benefit Plan" and collectively, "Benefit Plans"), should be aware that the use of additional contributions of cash outside of the Benefit Plan to exercise Rights may be treated as additional contributions to the Benefit Plan. When taken together with contributions previously made, such deemed additional contributions may be in excess of tax limitations and subject the Rights holder to excise taxes for excess or nondeductible contributions. In the case of Benefit Plans qualified under Section 401(a) of the Code, additional contributions could cause the maximum contribution limitations of Section 415 of the Code or other qualification rules to be violated. Benefit Plans contemplating making additional contributions to exercise Rights should consult with their legal and tax counsel prior to making such contributions.

Benefit Plans and other tax-exempt entities, including governmental plans, should also be aware that if they borrow to finance their exercise of Rights, they may become subject to the tax on unrelated business taxable income ("UBTI") under Section 511 of the Code. If any portion of an IRA is used as security for a loan, the portion so used may also be treated as distributed to the IRA depositor.

A Benefit Plan may also be subject to laws, such as ERISA, that impose certain requirements on the Benefit Plan and on those persons who are fiduciaries with respect to the Benefit Plans. Such requirements may include prudence and diversification requirements and require that investments be made in accordance with the documents governing the Benefit Plan. The exercise of Rights by a fiduciary for a Benefit Plan should be considered in light of such fiduciary requirements.

In addition, ERISA and the Code prohibit certain transactions involving the assets of a Benefit Plan and certain persons (referred to as "parties in interest" for purposes of ERISA and "disqualified persons" for purposes of the Code) having certain relationships to such Benefit Plans, unless a statutory or administrative exemption is applicable to the transaction. A party in interest or disqualified person who engages in a nonexempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and the Code (or with respect to certain Benefit Plans, such as IRAs, a prohibited transaction may cause the Benefit Plan to lose its tax-exempt status). In this regard, the U.S. Department of Labor has issued prohibited transaction class exemptions ("PTCEs") that may apply to the exercise of the Rights and holding of the Common Shares. These class exemptions include, without limitation, PTCE 84-14 respecting transactions determined by independent qualified professional asset managers, PTCE 90-1 respecting insurance company pooled separate accounts, PTCE 91-38 respecting bank collective investment funds, PTCE 95-60 respecting life insurance company general accounts and PTCE 96-23 respecting transactions determined by in-house asset managers, PTCE 84-24 governing purchases of shares in investment companies) and PTCE 75-1 respecting sales of securities. In addition, Section 408(b)(17) of ERISA and Section 4975(d)(20) of the Code each provides a limited exemption, commonly referred to as the "service provider exemption," from the prohibited transaction provisions of ERISA and Section 4975 of the Code for certain transactions between a Benefit Plan and a person that is a party in interest and/or a disqualified person (other than a fiduciary or an affiliate that, directly or indirectly, has or exercises any discretionary authority or control or renders any investment advice with respect to the assets of any Benefit Plan involved in the transaction) solely by reason of providing services to the Benefit Plan or by relationship to a service provider, provided that the Benefit Plan receives no less, nor pays no more, than adequate consideration. There can be no assurance that all of the conditions of any such exemptions or any other exemption will be satisfied at the time that the Rights are exercised, or thereafter while the Common Shares are held, if the facts relied upon for utilizing a prohibited transaction exemption change.

Due to the complexity of these rules and the penalties for noncompliance, fiduciaries of Benefit Plans should consult with their legal and tax counsel regarding the consequences of their exercise of Rights under ERISA, the Code and other similar laws.

SUMMARY OF FUND EXPENSES

The purpose of the table and the example below is to help you understand all fees and expenses that you, as a shareholder of Common Shares ("Common Shareholder"), would bear directly or indirectly. The table shows the expenses of the Fund as a percentage of the average net assets applicable to Common Shares, and not as a percentage of total assets or Managed Assets.

Shareholder Transaction Expenses
Offering Costs Borne by the Common Shareholders of the Fund (as a percentage of common net assets including proceeds of the offering)(1)			None
Offering Costs (as a percentage of the proceeds of the offering)(1)			None
Dividend Reinvestment Plan Fees(2)		$	2.50

Annual Expenses		As a Percentage of Net Assets Attributable to Common Shares(3)
Management Fees		1.04	%
Interest and Other Related Expenses(4)		2.15	%
Other Expenses(5)		0.10	%
Total Annual Expenses		3.29	%

Example

The following example illustrates the expenses that a Common Shareholder would pay on a $1,000 investment held for the time periods provided in the table, assuming a 5% annual total return. The example assumes that all dividends and other distributions are reinvested in the Fund and that the Fund's Annual Total Expenses, as provided above, remain the same.⁽¹⁾

1 Year		3 Years		5 Years		10 Years
$33		$101		$172		$359

The example should not be considered a representation of future expenses. Actual expenses may be greater or less than those shown above.

(1)	The example assumes that all dividends and distributions are reinvested at Common Shares NAV. Actual expenses may be greater or less than those assumed. Moreover, the Fund's actual rate of return may be greater or less than the hypothetical 5% return shown in the example.

TRADING AND NET ASSET VALUE INFORMATION

The following table shows for the periods indicated: (i) the high and low sales prices for the Common Shares reported as of the end of the day on the NYSE, (ii) the corresponding NAV per share, and (iii) the premium/(discount) to NAV per share at which the Common Shares were trading as of such date. The Fund's Common Shares have historically traded both at premiums and discounts in relation to the Fund's NAV per share. The Fund cannot predict whether its Common Shares will trade at a premium or discount to NAV in the future. The Board has currently determined that, at least annually, it will consider action that might be taken to reduce or eliminate any material discount from NAV in respect of Common Shares, which may include the repurchase of such shares in the open market or in private transactions, the making of a tender offer for such shares at NAV, or the conversion of the Fund to an open-end investment company. The Fund cannot assure you that its Board will decide to take any of these actions, or that share repurchases or tender offers will actually reduce market discount.

		Closing Market Price per Common Share				NAV per Common Share on Date of Market Price				Premium/(Discount) on Date of Market Price
Fiscal Quarter Ended		High		Low		High		Low		High		Low
July 2026		$ 10.57		$ 10.01		$ 10.50		$ 10.16		0.67%		(1.48)%
April 2026		$ 10.71		$ 10.01		$ 10.57		$ 10.17		1.32%		(1.57)%
January 2026		$ 10.74		$ 10.10		$ 10.63		$ 10.40		1.03%		(2.88)%
October 2025		$ 10.69		$ 9.97		$ 10.59		$ 9.91		0.94%		0.61%
July 2025		$ 10.65		$ 9.87		$ 10.48		$ 9.91		1.62%		(0.40)%
April 2025		$ 11.29		$ 9.75		$ 11.18		$ 10.39		0.98%		(6.16)%
January 2025		$ 11.61		$ 10.70		$ 11.47		$ 11.02		1.22%		(2.90)%
October 2024		$ 11.82		$ 10.72		$ 11.66		$ 11.73		1.37%		(8.61)%
July 2024		$ 10.87		$ 10.10		$ 11.53		$ 11.08		(5.72)%		(8.84)%
April 2024		$ 10.62		$ 9.92		$ 11.36		$ 11.03		(6.51)%		(10.06)%
January 2024		$ 10.05		$ 8.55		$ 11.04		$ 9.51		(8.97)%		(10.09)%

The NAV per Common Share, the market price and percentage of premium/(discount) to NAV per Common Share on October 16, 2026, was $9.28, $9.13, and (1.62)%, respectively. As of October 16, 2026, the Fund had 217,525,902 Common Shares outstanding, and net assets applicable to Common Shares of $2,017,986,666. See "Repurchase of Fund Shares; Conversion to Open-End Fund" in the accompanying prospectus.

USE OF PROCEEDS

Assuming the sale of all of the Common Shares offered through Rights under this Prospectus Supplement and the accompanying prospectus, based on the estimated Subscription Price of $8.60 and that the estimated expenses related to the Rights offering of $371,000 are paid by Nuveen Fund Advisors, the Fund estimates the net proceeds of the offering will be approximately $318,200,000. There is no guarantee that there will be any sales of Common Shares through Rights pursuant to this Prospectus Supplement and the accompanying prospectus. Actual sales, if any, of Common Shares through Rights under this Prospectus Supplement and the accompanying prospectus may be less than as set forth above. In addition, the price per share of any such sale may be greater or less than the price set forth above, depending on the market price of Common Shares at the time of any such sale. As a result, the actual net proceeds the Fund receives may be more or less than the amount of net proceeds estimated in this Prospectus Supplement.

The Fund intends to invest the net proceeds from the issuance of Rights hereunder in accordance with the Fund's investment objectives and policies as set forth in the accompanying prospectus. The Fund currently anticipates that it will be able to invest substantially all of the net proceeds in investments that meet the Fund's investment objectives and policies within approximately three months of the receipt of such proceeds; however, the identification of appropriate investment opportunities pursuant to the Fund's investment style or changes in market conditions may cause the investment period to extend as long as six months (the "invest-up period"). Pending investment, it is anticipated that the proceeds will be invested in short-term or long-term securities issued by the U.S. Government and its agencies or instrumentalities or in high-quality, short-term money market instruments. In addition, the Fund may use such proceeds to pay distributions to shareholders. Current market conditions may change and the Fund may not be able to invest the proceeds as planned. Immediately after the initial invest-up period, the Fund's portfolio allocations may vary over time consistent with the Fund's investment policies as described in the accompanying prospectus.

CAPITALIZATION

The Fund is issuing Rights to its Common Shareholders to subscribe for an aggregate of up to 37,000,000 of its Common Shares, $0.01 par value per share. There is no guarantee that there will be any sales of the Common Shares through Rights pursuant to this Prospectus Supplement and the accompanying prospectus.

The following table sets forth the Fund's capitalization (1) on a historical basis as of October 16, 2026 (unaudited); and (2) on a pro forma basis as adjusted to reflect the assumed sale of up to 37,000,000 Common Shares at $8.60 per share (the estimated Subscription Price), through a Rights offering under this Prospectus Supplement and the accompanying prospectus, and assuming that the expenses related to the Rights offering estimated at approximately $371,000 are paid by Nuveen Fund Advisors.

		As of October 16, 2026 (unaudited)			As Adjusted for Offering (unaudited)
Common Shares, $0.01 par value per share		$	2,175,259		$	2,545,259
Paid-in capital *		$	2,506,544,984		$	2,824,374,984
Total distributable earnings (loss)		$	(490,733,577	)	$	(490,733,577)
Net assets applicable to Common Shares		$	2,017,986,666		$	2,336,186,666
Common Shares			217,525,902			254,525,902
Net asset value		$	9.28		$	9.18

* As adjusted Paid-in Capital reflects the issuance of up to 37,000,000 Common Shares issued in the primary subscription at the estimated Subscription Price of $8.60.

SPECIAL CHARACTERISTICS AND RISKS OF THE RIGHTS OFFERING

Risk is inherent in all investing. Therefore, before investing in the Common Shares you should consider the risks associated with such an investment carefully. See "Risk Factors" in the accompanying prospectus. The following summarizes some of the matters that you should consider before investing in Common Shares through the Rights offering:

Dilution Risk. Record Date Shareholders who do not fully exercise their Rights will, at the completion of the Rights offering, own a smaller proportional interest in the Fund than owned prior to the Rights offering. The completion of the Rights offering will result in immediate voting dilution for such shareholders. You will also experience an immediate dilution of the aggregate NAV per Common Share if you do not fully participate in the Rights offering. You may also experience a reduction in the NAV per Common Share whether or not you exercise your Rights, as the Subscription Price may be below the Fund's NAV per Common Share on the Expiration Date, because:

●

the offered Common Shares may be sold at less than their current NAV; and

●

the number of Common Shares outstanding after the Rights offering may have increased proportionately more than the increase in the amount of the Fund's net assets.

The amount of such potential dilution is not currently determinable because it is not known how many Common Shares will be subscribed for, what the NAV per Common Share or market price of the Common Shares will be on the Expiration Date or what the Subscription Price per Common Share will be.

Furthermore, if you do not participate in an over-subscription privilege, if it is available, your percentage ownership may also be diluted. The Fund cannot state precisely the amount of dilution because it is not known at this time what the NAV per Common Share will be on the Expiration Date or what proportion of the Rights will be exercised or what the Subscription Price per Common Share will be. The impact of the Rights offering on NAV per Common Share pursuant to the Primary Subscription is shown by the following example, assuming the Rights offering is fully subscribed and the estimated Subscription Price of $8.60:

Assumes the Primary Subscription is fully subscribed(1)
NAV(2)		$	9.28
Subscription Price(3)		$	8.60
Reduction in NAV ($)		$	(0.10	)
Reduction in NAV (%)			(1.08	)%

	(1)	Actual amounts may vary due to rounding.
	(2)	For illustrative purposes only; reflects the Fund's NAV per Common Share as of October 16, 2026. It is not known at this time what the NAV per Common Share will be on the Expiration Date.
	(3)	For illustrative purposes only; reflects an estimated Subscription Price of $8.60 based upon 95% of the average of the last reported sales price of the Common Shares on the NYSE on October 16, 2026, and the four (4) immediately preceding trading days. It is not known at this time what the Subscription Price will be on the Expiration Date.

The impact of the Rights offering on NAV per Common Share pursuant to the Primary Subscription and Primary and Secondary Over-Subscription Privileges is shown by the following example that assumes that the Primary Subscription and Primary and Secondary Over-Subscription Privileges are fully subscribed with a $8.60 Subscription Price:

Assumes full subscription and 25% over-subscription⁽¹⁾

NAV(2)		$	9.28
Subscription Price(3)		$	8.60
Reduction in NAV ($)		$	(0.12	)
Reduction in NAV (%)			(1.29	)%

(1)

Actual amounts may vary due to rounding.

(2)

For illustrative purposes only; reflects the Fund's NAV per Common Share as of October 16, 2026. It is not known at this time what the NAV per Common Share will be on the Expiration Date.

(3)

For illustrative purposes only; reflects an estimated Subscription Price of $8.60 based upon 95% of the average of the last reported sales price of the Common Share on the NYSE on October 16, 2026, and the four (4) immediately preceding trading days. It is not known at this time what the Subscription Price will be on the Expiration Date.

If you do not wish to exercise your Rights, you should consider selling them as set forth in this Prospectus Supplement. Any cash you receive from selling your Rights may serve as partial compensation for dilution of your interest in the Fund. The Fund cannot give assurance, however, that a market for the Rights will develop or be maintained or that the Rights will have any marketable value.

The Fund's largest shareholders could increase their percentage ownership in the Fund through the exercise of the primary subscription and over-subscription privilege.

Risks of Investing in Rights. Shares of closed-end funds, such as the Fund, frequently trade at a discount to NAV. Accordingly, the Subscription Price may be greater than the market price of the Common Shares on the Expiration Date. If that is the case, the Rights will have no value, and a person who exercises their Rights will experience an immediate loss of value. Further, because the exercise of Rights is irrevocable, you will not be able to revoke your subscription if the market price of the Common Shares decreases below the Subscription Price prior to delivery of your Common Shares. Moreover, the Fund cannot assure you that you will ever be able to sell the Common Shares that you received in the Rights offering at a price equal to or greater than the Subscription Price.

No Assurance of Active Trading Market Risk. Although the Rights are approved for listing on the NYSE, there can be no assurance that an active trading market will develop or be maintained for the Rights. If a trading market is not developed or maintained, you may not be able to transfer your Rights or may have to sell them at an unfavorable price. The transferability of Rights is not guaranteed and investors who do not exercise their Rights prior to the Expiration Date and are unable or unwilling to sell their Rights in the secondary market will realize no value for their Rights.

Risks of Increases in Share Price Volatility and Decreases in Share Price. The Rights offering may result in an increase in trading of the Common Shares, which may increase volatility in the market price of the Common Shares. The Rights offering may result in an increase in the number of Common Shareholders wishing to sell their Common Shares, which would exert downward price pressure on the price of Common Shares.

Risk of Decreased Liquidity Despite Larger Float. Although the Rights offering will increase the number of Common Shares outstanding, there can be no assurance that the volume of trading in the Common Shares will increase proportionately. As a result, the Rights offering may not materially improve the liquidity of the Common Shares on the secondary market, which could lead to wider bid/ask spreads, increased volatility and greater variances between the market price of the Common Shares and their underlying value.

Under-Subscription Risk. It is possible that the Rights offering will not be fully subscribed. Under-subscription of the Rights offering would have an impact on the net proceeds of the Rights offering and whether the Fund achieves any benefits.

Over-Subscription Risk. Record Date Shareholders who fully exercise all Rights initially issued to them will be entitled to subscribe for an additional number of Common Shares by exercising their over-subscription privileges. The over-subscription privileges will generally be allocated pro rata among Record Date Shareholders who over-subscribed based on the number of Rights issued to them by the Fund. The Fund cannot guarantee that you will receive any or the entire number of Common Shares for which you over-subscribed. If the pro-rated number of Common Shares allocated to you in connection with your over-subscription privileges is less than your request, then the excess funds held by the Subscription Agent on your behalf will be returned to you, without interest, as soon as practicable after the Rights offering has expired and all pro-rating calculations and reductions contemplated by the terms of the Rights offering have been effected, and the Fund will have no further obligation to you.

No Assurance or Accretion in NAV or Distributions. Although the Rights offering will increase the Fund's assets, there can be no assurance that the Rights offering will be accretive to the Fund's NAV per Common Share or its ability to sustain or increase distributions. Investment returns on the proceeds from the Rights offering may be lower than current portfolio returns, and the Fund's distribution rate per Common Share may decline.

Risk of Delayed Delivery of Common Shares. If you exercise Rights, you may not be able to resell the Common Shares that you receive in the Rights offering until you, or your custodian bank, broker, dealer or other nominee, if applicable, have received those Common Shares. Moreover, you will have no rights as a shareholder of the Common Shares you received in the Rights offering until the Fund issues those Common Shares to you. Although the Fund will endeavor to issue the Common Shares as soon as practicable after completion of the Rights offering, and after all necessary calculations have been completed, there may be a delay between the Expiration Date and the time that the Common Shares are issued.

Risk that Market Conditions May Impact Use of Proceeds. Although the Fund intends to invest the proceeds from the Rights offering as described herein, market or other conditions at the time of investment may result in the Fund making investments with different risk or return characteristics, or at less favorable yields, than currently anticipated, which could adversely affect the Fund's performance and distribution levels.

Risk of Rejection of Exercise of Rights. Record Date Shareholders who desire to subscribe for Common Shares in the Rights offering must act promptly to ensure that all required forms and payments are actually received by the Subscription Agent prior to the Expiration Date. If you are a beneficial owner of Common Shares, you must act promptly to ensure that your custodian bank, broker, dealer or other nominee acts for you and that all required forms and payments are actually received by the Subscription Agent prior to the Expiration Date. Your nominee may establish a deadline prior to the Expiration Date by which you must provide it with your instructions to exercise your subscription rights and payment for your Common Shares. The Fund will not be responsible if your custodian bank, broker, dealer or nominee fails to ensure that all required forms and payments are actually received by the Subscription Agent prior to the Expiration Date. If you fail to complete and sign the required Subscription Certificate, send an incorrect payment amount, or otherwise fail to follow the subscription procedures that apply to your desired transaction, the Fund or the Subscription Agent may, depending on the circumstances, reject your subscription or accept it to the extent of the payment received. Neither the Fund nor the Subscription Agent will be under any duty to give notification of any defect or irregularity in connection with the submission of Subscription Certificates or incur any liability for failure to give such notification. The Fund has the sole discretion to determine whether a subscription exercise properly follows the subscription procedures.

Risk of Termination of Rights Offering. The Fund reserves the right to terminate, amend or extend the Rights offering at any time for any reason before 5:00 p.m., Eastern Time, on the Expiration Date. You will not earn any interest on any payment of the Subscription Price you have made while it is being held by the Subscription Agent pending the termination of the Rights offering, even if the Fund amends the terms of the Rights offering to extend the Subscription Period. If the Fund terminates the Rights offering, neither the Fund, the Subscription Agent, your broker, nor any other party will have any obligation to you, except to return any payment of the Subscription Price you have made, which will not accrue interest.

TAXATION

The following is a general summary of the U.S. federal income tax consequences of the Rights offering to Record Date Shareholders who are U.S. persons for U.S. federal income tax purposes. The following summary supplements the discussion set forth in the accompanying prospectus and SAI and is subject to the qualifications and assumptions set forth therein. The discussion set forth herein does not constitute tax advice and potential investors are urged to consult their own tax advisers to determine the tax consequences of investing in the Fund.

Please refer to the "Tax Matters" sections in the accompanying prospectus and SAI for a description of the consequences of investing in the Common Shares. Special tax considerations relating to this Rights offering are summarized below:

●

The value of a Right will not be includible in the income of a Common Shareholder at the time the subscription Right is issued.

●

The basis of a Right issued to a Common Shareholder will be zero, and the basis of the share with respect to which the Right was issued (the old share) will remain unchanged, unless either (a) the fair market value of the Right on the date of distribution is at least 15% of the fair market value of the old share, or (b) such Common Shareholder affirmatively elects (in the manner set out in Treasury regulations under the Code) to allocate to the Right a portion of the basis of the old share. If either (a) or (b) applies, such Common Shareholder must allocate basis between the old share and the Right in proportion to their fair market values on the date of distribution.

●

The basis of a Right purchased in the market will generally be its purchase price.

●

The holding period of a Right issued to a Common Shareholder will include the holding period of the old share.

●

No loss will be recognized by a Common Shareholder if a Right distributed to such Common Shareholder expires unexercised because the basis of the old share may be allocated to a Right only if the Right is exercised. If a Right that has been purchased in the market expires unexercised, there will be a recognized loss equal to the basis of the Right.

●

Any gain or loss on the sale of a Right will be a capital gain or loss if the Right is held as a capital asset (which in the case of a Right issued to Record Date Shareholders will depend on whether the old share is held as a capital asset), and will be a long term capital gain or loss if the holding period is deemed to exceed one year.

●

No gain or loss will be recognized by a Common Shareholder upon the exercise of a Right, and the basis of any Common Share acquired upon exercise (the new Common Share) will equal the sum of the basis, if any, of the Right and the subscription price for the new Common Share. The holding period for the new Common Share will begin on the date when the Right is exercised (or, in the case of a Right purchased in the market, potentially the day after the date of exercise).

The foregoing is a general and abbreviated summary of the provisions of the Code and the Treasury regulations in effect as they directly govern the taxation of the Fund and holders of its Common Shares, with respect to U.S. federal income taxation only. Other tax issues such as state and local taxation may apply. Investors are urged to consult their own tax advisers to determine the tax consequences of investing in the Fund. These provisions are subject to change by legislative or administrative action, and any such change may be retroactive.

LEGAL MATTERS

Certain legal matters in connection with the Common Shares will be passed upon for the Fund by Stradley Ronon Stevens & Young, LLP, located at 2005 Market Street, Suite 2600, Philadelphia, PA 19103. Stradley Ronon Stevens & Young, LLP may rely as to certain matters of Massachusetts law on the opinion of Morgan, Lewis & Bockius LLP.

AVAILABLE INFORMATION

The Fund is subject to the informational requirements of the Securities Exchange Act of 1934, as amended (the "Exchange Act") and the 1940 Act and is required to file reports, proxy statements and other information with the SEC. Reports, proxy statements, and other information about the Fund can be inspected at the offices of the NYSE.

This Prospectus Supplement does not contain all of the information in the Fund's Registration Statement, including amendments, exhibits, and schedules. Additional information about the Fund and the Common Shares can be found in the Fund's Registration Statement (including amendments, sexhibits, and schedules) on Form N-2 filed with the SEC. The SEC maintains a website (www.sec.gov) that contains the Fund's Registration Statement, other documents incorporated by reference, and other information the Fund has filed electronically with the SEC, including proxy statements and reports filed under the Exchange Act.

Prospectus Summary			1
Summary of Fund Expenses			7
Financial Highlights			7
Trading and Net Asset Value Information			7
The Fund			7
Use of Proceeds			8
The Fund's Investments			8
Use of Leverage			9
Risk Factors			13
Management of the Fund			13
Net Asset Value			16
Distributions			17
Dividend Reinvestment Plan			17
Plan of Distribution			17
Description of Shares			20
Rights Offerings			23
Certain Provisions in the Declaration of Trust and By-Laws			24
Repurchase of Fund Shares; Conversion to Open-End Fund			26
Tax Matters			27
Custodian and Transfer Agent			29
Independent Registered Public Accounting Firm			29
Legal Matters			29
Available Information			29
Incorporation By Reference			30

The Fund

Nuveen Municipal High Income Opportunity Fund (the "Fund") is a diversified, closed-end management investment company. See "The Fund." The Fund's common shares, $0.01 par value per share ("Common Shares"), are traded on the New York Stock Exchange (the "NYSE") under the symbol "NMZ." Preferred Shares and/or Rights issued by the Fund may also be listed on a securities exchange.

The closing price of the Common Shares, as reported by the NYSE on February 22, 2024, was $10.33 per Common Share. The net asset value ("NAV") of the Common Shares at the close of business on that same date was $11.17 per Common Share. As of January 31, 2024, the Fund had 110,539,338 Common Shares outstanding and net assets of $1,230,630,689. See "Description of Shares."

The Offering

The Fund may offer, from time to time, in one or more offerings, Common Shares, preferred shares ("Preferred Shares"), and/or subscription rights to purchase Common Shares ("Rights," and collectively with Common Shares and Preferred Shares, "Securities"), in any combination, on terms to be determined at the time of the offering. The Fund may offer and sell such Securities directly to one or more purchasers, to or through underwriters, through dealers or agents that the Fund designates from time to time, or through a combination of these methods. The prospectus supplement relating to any offering of Securities will describe such offering, including, as applicable, the names of any underwriters, dealers or agents and information regarding any applicable purchase price, fee, commission or discount arrangements made with those underwriters, dealers or agents or the basis upon which such amount may be calculated. For more information about the manners in which the Fund may offer Securities, see "Plan of Distribution." The prospectus supplement relating to any Rights offering will set forth the number of Common Shares issuable upon the exercise of each Right (or number of Rights) and the other terms of such Rights offering. The minimum price on any day at which the Common Shares may be sold will not be less than the NAV per Common Share at the time of the offering plus the per share amount of any underwriting commission or discount; provided that Rights offerings that meet certain conditions may be offered at a price below the then current NAV. See "Rights Offerings."

The Fund may not sell any Securities through agents, underwriters or dealers without delivery, or deemed delivery, of a prospectus, including the appropriate prospectus supplement, describing the method and terms of the particular offering of such Securities. You should read this Prospectus and the applicable prospectus supplement carefully before you invest in our Securities.

Investment Objectives and Policies

Please refer to the section of the Fund's most recent annual report on Form N-CSR entitled "Shareholder Update-Current Investment Objectives, Investment Policies and Principal Risks of the Funds-Investment Objectives" and "-Investment Policies," as such investment objectives and investment policies may be supplemented from time to time, which are incorporated by reference herein, for a discussion of the Fund's investment objectives and policies.

There can be no assurance that such strategies will be successful. For a more complete discussion of the Fund's portfolio composition and its corresponding risks, see "The Fund's Investments" and "Risk Factors."

Investment Adviser

Nuveen Fund Advisors, LLC ("Nuveen Fund Advisors"), the Fund's investment adviser, is responsible for overseeing the Fund's overall investment strategy and its implementation. Nuveen Fund Advisors offers advisory and investment management services to a broad range of investment company clients. Nuveen Fund Advisors has overall responsibility for management of the Fund, oversees the management of the Fund's portfolio, manages the Fund's business affairs and provides certain clerical, bookkeeping and other administrative services. Nuveen Fund Advisors is located at 333 West Wacker Drive, Chicago, Illinois 60606. Nuveen Fund Advisors is an indirect subsidiary of Nuveen, LLC ("Nuveen"), the investment management arm of Teachers Insurance and Annuity Association of America ("TIAA"). TIAA is a life insurance company founded in 1918 by the Carnegie Foundation for the Advancement of Teaching and is the companion organization of College Retirement Equities Fund. As of December 31, 2023, Nuveen managed approximately $1.2 trillion in assets, of which approximately $140.2 billion was managed by Nuveen Fund Advisors.

Sub-Adviser

Nuveen Asset Management, LLC ("Nuveen Asset Management") serves as the Fund's sub-adviser. Nuveen Asset Management, a registered investment adviser, is a wholly-owned subsidiary of Nuveen Fund Advisors. Nuveen Asset Management oversees the day-to-day investment operations of the Fund.

Use of Leverage

The Fund uses leverage to pursue its investment objectives. The Fund may use leverage to the extent permitted by the Investment Company Act of 1940, as amended (the "1940 Act"). The Fund may source leverage through a number of methods, including the issuance of Preferred Shares, investment in inverse floating rate securities, entering into reverse repurchase agreements (effectively a secured borrowing) and borrowings (subject to certain investment restrictions). The Fund may also use certain derivatives that have the economic effect of leverage by creating additional investment exposure.

Currently, the Fund employs leverage through its outstanding Adjustable Rate MuniFund Term Preferred Shares ("AMTP Shares"),

which have seniority over the Common Shares. The Fund also currently invests in residual interest certificates of tender option bond trusts, also called inverse floating rate securities, that have the economic effect of leverage because the Fund's investment exposure to the underlying bonds held by the trust have been effectively financed by the trust's issuance of floating rate certificates. For the fiscal year ended October 31, 2023, the average liquidation value of the AMTP Shares outstanding and the annualized dividend rate on the AMTP Shares were $357 million and 4.10%, respectively. As of January 31, 2024, the Fund's leverage through preferred shares and through investments in inverse floating rate securities was approximately 39% of its Managed Assets.

The Fund may also borrow for temporary purposes as permitted by the 1940 Act. The Fund, along with certain other funds managed by Nuveen Fund Advisors (the "Participating Funds"), are party to a committed unsecured credit facility (the "Facility") provided by a group of lenders, under which Participating Funds may borrow for temporary purposes only. Outstanding balances drawn by the Fund, or any other Participating Fund, will bear interest at a variable rate and is the liability of such Fund. The Facility is not intended for sustained levered investment purposes. A large portion of the Facility's capacity (and corresponding annual costs, excluding interest cost) is currently allocated by Nuveen Fund Advisors to a small number of Participating Funds, which does not include the Fund. The Facility has a 364-day term and will expire on June 19, 2024 unless extended or renewed.

The Fund may reduce or increase leverage based upon changes in market conditions and anticipates that its leverage ratio will vary from time to time based upon variations in the value of the Fund's holdings. So long as the rate of net income received on the Fund's investments exceeds the then current expense on any leverage, leverage will generate more net income than if the Fund had not used leverage. If so, the excess net income will be available to pay higher distributions to Common Shareholders. However, if the rate of net income received from the Fund's portfolio investments is less than the then current expense on outstanding leverage, the Fund may be required to utilize other Fund assets to make expense payments on outstanding leverage, which may result in a decline in Common Share NAV and reduced net investment income available for distribution to Common Shareholders.

The Fund pays a management fee to Nuveen Fund Advisors (which in turn pays a portion of its fee to Nuveen Asset Management) based on a percentage of Managed Assets. Managed Assets for this purpose includes the proceeds realized and managed from the Fund's use of leverage as set forth in the Fund's investment management agreement. Because Managed Assets include the Fund's net assets as well as assets that are attributable to the Fund's use of leverage, it is anticipated that the Fund's Managed Assets will be greater than its net

assets. Nuveen Fund Advisors and Nuveen Asset Management are responsible for using leverage to pursue the Fund's investment objectives, and base their decision regarding whether and how much leverage to use for the Fund on their assessment of whether such use of leverage will advance the Fund's investment objectives. However, a decision to employ or increase the Fund's leverage will have the effect, all other things being equal, of increasing Managed Assets and therefore Nuveen Fund Advisors' and Nuveen Asset Management's fees. Thus, Nuveen Fund Advisors and Nuveen Asset Management may have a conflict of interest in determining whether the Fund should use or increase leverage. Nuveen Fund Advisors and Nuveen Asset Management will seek to manage that potential conflict by only employing or increasing the Fund's use of leverage when they determine that such increase is in the best interest of the Fund and is consistent with the Fund's investment objectives, and by periodically reviewing the Fund's performance and use of leverage with the Fund's Board of Trustees (the "Board").

The use of leverage creates additional risks for Common Shareholders, including increased variability of the Fund's NAV, net income and distributions in relation to market changes. There is no assurance that the Fund will continue to use leverage or that the Fund's use of leverage will work as planned or achieve its goals.

Distributions

The Fund pays regular monthly cash distributions to Common Shareholders (stated in terms of a fixed cents per Common Share dividend distribution rate which may be set from time to time). The Fund intends to distribute all or substantially all of its net investment income each year through its regular monthly distributions and to distribute realized capital gains at least annually. In addition, in any monthly period, to maintain its declared per common share distribution amount, the Fund may distribute more or less than its net investment income during the period. In the event the Fund distributes more than its net investment income, such distributions may also include realized gains and/or a return of capital. To the extent that a distribution includes a return of capital the NAV per share may erode. If a distribution includes anything other than net investment income, the Fund provides a notice of the best estimate of its distribution sources at the time. See "Distributions."

Custodian and Transfer Agent

State Street Bank and Trust Company serves as the Fund's custodian, and Computershare Inc. and Computershare Trust Company, N.A. serves as the Fund's transfer agent for the Common Shares. The corresponding agent for any Preferred Shares will be identified in the related prospectus supplement. See "Custodian and Transfer Agent."

Risk Factors

Investment in the Fund involves risk. The Fund is designed as a long-term investment and not as a trading vehicle. The Fund is not intended to be a complete investment program. Please refer to the section of the Fund's most recent annual report on Form N-CSR entitled "Shareholder Update-Current Investment Objectives, Investment Policies and Principal Risks of the Funds-Principal Risks of the Funds," as such principal risks may be supplemented from time to time, which is incorporated by reference herein, for a discussion of the principal risks you should consider before making an investment in the Fund. The specific risks applicable to a particular offering of Securities will be set forth in the related prospectus supplement.

Use of Proceeds

Unless otherwise specified in a prospectus supplement, the Fund will use the net proceeds from any offering of Securities, pursuant to this Prospectus, to make investments in accordance with the Fund's investment objectives. See "Use of Proceeds."

Federal Income Tax

The Fund has elected to be treated, and intends to qualify each year, as a regulated investment company ("RIC") under Subchapter M of the Internal Revenue Code of 1986, as amended (the "Code"). To qualify for the favorable U.S. federal income tax treatment generally accorded to a RIC under Subchapter M of the Code the Fund must, among other requirements, derive in each taxable year at least 90% of its gross income from certain prescribed sources and satisfy a diversification test on a quarterly basis. If the Fund fails to satisfy the qualifying income or diversification requirements in any taxable year, the Fund may be eligible for relief provisions if the failures are due to reasonable cause and not willful neglect and if a penalty tax is paid with respect to each failure to satisfy the applicable requirements. Additionally, relief is provided for certain de minimis failures of the diversification requirements where the Fund corrects the failure within a specified period. In order to be eligible for the relief provisions with respect to a failure to meet the diversification requirements, the Fund may be required to dispose of certain assets. If these relief provisions were not available to the Fund and it were to fail to qualify for treatment as a RIC for a taxable year, all of its taxable income (including its net capital gain) would be subject to tax at the 21% regular corporate rate without any deduction for distributions to shareholders, and such distributions would be taxable as ordinary dividends to the extent of the Fund's current and accumulated earnings and profits. To qualify to pay exempt-interest dividends, which are treated as items of interest excludable from gross income for federal income tax purposes, at least 50% of the value of the total assets of the Fund must consist of obligations exempt from regular income tax as of the close of each quarter of the Fund's taxable year. If the proportion of taxable investments held by the Fund exceeds 50% of the Fund's total assets as of the close of any quarter of any Fund taxable year, the Fund will not for that taxable year satisfy the general eligibility test that otherwise permits it to pay exempt-interest dividends.

Governing Law

The Fund's Declaration of Trust (the "Declaration of Trust") is, and each Statement and Statement Supplement for Preferred Shares will be, governed by the laws of the Commonwealth of Massachusetts.

Title of Class		Amount Authorized				Amount Held by the Fund or for its Account				Amount Outstanding
Common Shares			Unlimited				0				110,539,338
Preferred Shares			Unlimited				-				-
Series 2028 AMTP Shares			870				0				870
Series 2031 AMTP Shares			1,700				0				1,700
Series 2032 AMTP Shares			1,000				0				1,000

Average Daily Managed Assets*		Fund-Level Fee Rate
For the first $125 million			0.5500	%
For the next $125 million			0.5375	%
For the next $250 million			0.5250	%
For the next $500 million			0.5125	%
For the next $1 billion			0.5000	%
For the next $3 billion			0.4750	%
For managed assets over $5 billion			0.4625	%