I think it depends on what you want to do. I am not up on all of the NP scopes of practice, but the one's I worked with in AZ did EXACTLY the same as our PA's in the cardiology clinic and in rounds at the hospital. Our NP did not do ANY of the nursing duties. She was strictly a mid-level provider like the PA's.
My point is that more than 1 yr of experience might not be that beneficial. Well, experience never hurts, but I think you know what I mean. Why put your life on hold? Go full force while you have it in you and go to NP school as soon as you can get in. Just my opinion.
As an NP, you might be slightly deficient in some of the science areas compared to PA curriculum. However, this could me made up for with your own learning. I could be wrong, maybe the NP curriculum is very similar to PA. Not sure? I do know that PA curriculum is sort of like a mini-medical school. 🙂