I am in UTA's PMHNP program. Most of the basic classes can all be taken totally online, but once you reach the psych classes you can expect to meet on campus about 4 times a semester.
I started this program in August 2017. It is a hard program but it is doable. My original degree plan had me graduating in 4.5 years, but I had an advisor make some changes and now I will graduate in August 2020. I think 3 years is pretty much the quickest this program can be finished in. Let me know if you have any more questions.