It's quite a personal decision based on a variety of factors, so there's really no easy answer. For example, some CEP students chose ASU because they had a sibling or parent who went there, or they liked the idea of a "big name" university, or they had a GI Bill that was paying their way and hence money wasn't an issue (ASU was among the most expensive choices). Same for NAU - people loved the big name, plus they liked the program at NAU which has a great reputation, for example. Additionally NAU is cheaper. However, NAU has more pre-reqs which means more classes to pay for to get in......so you can see how each has pros and cons.
Do you have the list of university choices? It's available on the CEP webpage. I would encourage you to read each brochure thoroughly to get a feel for the program they offer. Each one is going to be similar- after all they are all majoring in nursing - but each is slightly different, and you'll want to go with which one appeals to you the most.
For me, personally, I ruled out 2 of the universities because they were not part of the financial consortium agreement. That is important if you will be using financial aid such as a Pell Grant. That left me with 4 choices. I ruled out ASU based on cost, and I ruled out NAU based on all the additional pre-reqs they required...I personally felt I had taken enough classes without adding 6 more to my list just to get my foot in the door at NAU! But, again, that is my personal take on it - loads of people chose NAU and I'm sure they are thrilled with their choice.
After those 2 were out I was left with UIU (Upper Iowa Uni) and OU (Ottawa Uni). Of those tow, I preferred the program and pricing at Ottawa, so I went with Ottawa. Additionally, Ottawa was very good at responding to all my messages and providing me with all the info I needed. The enrollment process with them was easy and smooth. They also have several brick-and-mortar places in the valley, with a new 4-year University campus that just opened its doors this fall in Surprise (West Valley), so I felt that I always had somewhere to go to talk face-to-face if I got really stuck or needed help.
So far I've been really happy with my decision. The program is challenging and the standards are high. I can't speak of the other programs, but I really like the way they have laid out the curriculum so that the demands ebb and flow based on my "in-person" classes at the community college. In other words, there are more online classes when there are less classes in-person (such as the semester before you start in-person, and the summer semester) and less online while you are busy in-person or in clinicals at the hospital. If you stay on pace though, you should graduate at about the same time with both degrees.