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 who 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 either adopt the Act or laws comparable to the Act.