Nano Nuclear Energy Inc 股票发行说明书（2026年02月20日版）

Up to 677,812 Shares of Common Stock under theNano Nuclear Energy Inc. 2025 Equity Incentive Plan This Prospectus Supplement, dated February 20, 2026 (this “Supplement”), supplements the reoffer prospectus (the “ReofferProspectus”) filed as part of the Registration Statement on Form S-8 filed by Nano Nuclear Energy Inc. (the “Company”, “us”, “our”or “we”) with the U.S. Securities and Exchange Commission (the “SEC”) on May 23, 2025, relating to the resale of common stock,par value $0.0001 per share (the “Common Stock”), of the Company which may be offered and sold from time to time by certain ofour executive officers and directors (the “Selling Stockholders”) who may be deemed “affiliates” of the Company as defined in Rule405 under the Securities Act of 1933, as amended (the “Securities Act”), who have acquired or will acquire such shares in connectionwith the exercise of stock options granted, and with stock or other awards made, and with the purchase of stock, under the Company’s2025 Equity Incentive Plan (the “2025 Plan”). This Supplement covers 677,812 shares of Common Stock (the “Shares”), including (i) You should read this Supplement in conjunction with the Reoffer Prospectus. This Supplement is qualified by reference to theReoffer Prospectus, except to the extent the information in this Supplement supersedes the information contained in the Reoffer Our Common Stock is quoted on the Nasdaq Capital Market under the symbol “NNE.” On February 19, 2026, the closingsales price of our Common Stock on the Nasdaq Capital Market was $25.66 per share. The Shares may be offered for resale from time to time by any or all of the Selling Stockholders, or their permittedtransferees, through public or private transactions, at fixed prices, prevailing market prices at the time of sale, prices related to theprevailing market prices, varying prices determined at the time of sale or negotiated prices. See “Plan of Distribution” in the ReofferProspectus. Sales may be made through underwriters, broker-dealers or agents, who are expected to receive compensation in the form The Selling Stockholders and participating underwriters, brokers and dealers may be deemed to be “underwriters” within themeaning of the Securities Act, in which event any profit on the sale of shares of those Selling Stockholders and any commissions or An investment in our Common Stock is speculative and subject to significant risk. You should carefully read andconsider the risk factors under Item 1A beginning on page 27 of our Annual Report on Form 10-K for the year endedSeptember 30, 2025 and Item 1A on page 38 of our Quarterly Report on Form 10-Q for the three months ended December 31, Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed uponthe adequacy or accuracy of the Reoffer Prospectus or this Supplement. Any representation to the contrary is a criminal The information set forth under the caption “Selling Stockholders” in the Reoffer Prospectus is amended and restated in itsentirety as set forth below and is provided for the primary purpose of updating the table of the Selling Stockholders contained in theReoffer Prospectus. The date of this Supplement is February 20, 2026 SELLING STOCKHOLDERS The Reoffer Prospectus relates to the offer and sale, from time to time, by the Selling Stockholders named herein, or theirpermitted transferees, of shares of our Common Stock issued to the Selling Stockholders under the 2025 Plan, as supplemented by thisSupplement. The following table sets forth the names of the Selling Stockholders, the number of shares of Common Stock owned by eachof them as of the date of this Supplement, the number of shares of Common Stock that they may offer pursuant to this Supplement, We cannot advise you as to whether the Selling Stockholders will in fact sell any or all of their Common Stock. The SellingStockholders may offer all or part of the Common Stock for resale from time to time through public or private transactions, at fixedprices, prevailing market prices at the time of sale, prices related to the prevailing market prices, varying prices determined at the timeof sale or negotiated prices. Because the Selling Stockholders may offer all, some or none of their securities, no definitive estimate asto the number of shares of Common Stock that will be held by the Selling Stockholders after an offering can be provided. The Selling Beneficial ownership is determined according to the rules of the SEC, which generally provide that a person has beneficialownership of a security if he, she or it possesses sole or shared voting or investment power over that security. Therefore, beneficialownership of the Common Stock by each Selling Stockholder includes Common Stock that is currently exercisable, convertible, or Unless otherwise indicated, we believe that all persons named in the table below have sole voting and investment power withrespect to Common Stock benef