In my opinion, easiest would be your AA from Excelsior college. I don't know if it is an AA in nuclear engineering technology or what it's exactly called. Just check out the program, do the enrollment process and start taking as many or as little classes as you want.
I received 72 credits from my Navy experience, separating as an E-5. That plus 9 more from previous college credit and I'm looking at 5 semesters, at about 8 credits a semester, to get my B.S..