I can try to answer it my son is a Navy nuke student. It takes 2 years of training to become one. He has another 6 months of training left.
The amount of college credits you earn depends on which nuclear rating you are and which college you apply to; some give more credits than others. This varies by a lot.
The most credits is if you are a nuclear Electronics Technician. You Navy training will be acredited 86 credit hours by ACE. EMs get 85 credits and MMs get 75 credits.
You cannot get a 4-5 year enlistment as a Navy nuke. The program requires 6 years of active duty, the first 2 years of that is your nuclear traning. Your starting pay depends on whether you go in the nuclear field after the Navy and what watches you earn. If you earn EWS (engineering watch supervisor) you can go right to Senior Reactor Operator training at a utility this is paid training. Same thing and slightly better is if you qualify for EOOW (engineering officer of the watch). Careers include nuclear reactor operator, also jobs in the semiconductor industry, petroleum industry, electric power industry (non nuclear), quality assurance, and the defense industry. Starting salaries vary but after a couple year figure on making over $100,000 a year. Good luck.