According to your post, you did not default on your credit card until some time while you were living in NV. That is when the SOL would normally accrue. But you were not in Texas so the SOL (whatever that period is determined to be) did not start to run until you returned to Texas.
Claiming that a SOL has run out is basically an affirmative defense to a lawsuit. You can't discharge a debt by claiming the SOL has run.
Since you have not yet been sued, there is nothing to prove (when you returned to Texas). I believe that the CC company has 4 years for debt collection. So you can wait to be sued or try to work something out with the CC company to pay off the debt. However, any payment you make will reset the SOL clock.

