If one of your W-2s has an amount in Box 16 and identifies the state as "TX" (Box 15), it really doesn't make any difference whether you enter it or not.
As a general rule, we recommend entering your Form W-2 information exactly as you received it. In many cases, the W-2 software automatically enters state wages even when the state doesn't have an income tax. Technically, they are still "state wages" even if not taxed.
(I import a W-2 with FL information in Boxes 15 and 16, and the program has no problem treating it as not taxable by the state.