What PTE score do you need for UNLV?

Both pages say scores must be less than two years old at the time of application. You can send official scores through the testing agency or email unofficial reports; if you are admitted on unofficial scores, admission is conditional on official scores arriving early in your first semester. PTE Academic Online and PTE Core are not mentioned.

For comparison, UNLV asks IELTS Academic 6.5 with no band below 6.0 for graduate study against PTE 65 (59), and 6.0 with no band below 5.5 for undergraduates against PTE 59 (50).

The undergraduate page says Fast Track students are tested before arrival and placed in a level. After completing Level 4 (at least one semester, at most two years) with a C or better in every course, they meet the English requirement without a new test and their degree application is resubmitted with no further fee.

Requirements vary by programme and change between admissions cycles. The score that binds you is the one on your UNLV programme page and in your offer letter, so check it there before you book a test.