First, go to www.ncsbn.com
to see if Utah is a "Compact state". If it is, she can work in Texas using her Utah license. Compact states honor one another's license, but once you establish residency, you must have a license in that state, so she will need to apply for a TX license.
Go to www.bne.state.tx.us
for the Board of Nurse Examiners in TX. They have applications online. I recommend clicking on "Table of Contents" then, in the search window, type in a keyword to find more info on a given topic.
Now, as for reciprocal licensure, all states have that. It just means you don't have to take state boards again, just apply for license in the new state.
TX is fingerprinting new applicants now and doing criminal background check. The reason I mention it is because I have had new employees blow it off thinking it non-impt. However, it is mandatory.
PM me if you need more info. and hope the move is a safe one.