Internet Tax Nondiscrimination Act

Expresses the sense of Congress that elements of a State law providing for a simplified sales and use tax system for remote sales should include, among other things: (1) a centralized, one-stop, multi-State registration system for sellers; (2) uniform definitions for goods or services that are included in the tax base; (3) uniform and simple rules for attributing transactions to particular taxing jurisdictions; (4) uniform procedures for the certification of software that sellers rely on to determine State and local use tax rates and taxability; and (5) uniform electronic filing and remittance methods.

Prohibits a State requiring a seller who lacks nexus with, or a tax obligation to, the State from collecting or remitting sales or use taxes on any sales in that State until Congress provides such authority to the States by a specified joint resolution.