Gigabit Opportunity Act This bill amends the Internal Revenue Code to authorize the designation of qualified gigabit opportunity zones in low-income communities and to provide tax incentives for investments in the zones. Governors may submit nominations for a limited number of qualified gigabit opportunity zones in low-income communities to the Department of the Treasury for certification and designation. Governors must give particular consideration to areas that: are facing obstacles to economic development due to a lack of geographic broadband coverage or speed; are the focus of mutually reinforcing state, local, or private economic development initiatives; are poised for economic growth that requires access to high speed broadband for commercial purposes; and represent the areas of a state where such service would result in the highest return on investment. For eligible taxpayers that sell certain broadband services, the bill allows: (1) deferrals, reductions, or exemptions from taxes on capital gains invested in certain property used to provide broadband services in a zone (depending on how long the property is held), and (2) immediate expensing of the costs of the property. The bill also allows tax-exempt private activity bonds to be used for certain broadband projects in the zones. Within one year of enactment of this bill, the Federal Communications Commission must publish a Uniform Model Broadband Deployment Act containing laws for the state regulation of the deployment of broadband services. Qualified zones must adopt either the Act or laws comparable to the Act.