Whats the best assignment?
Answer:
if you would be happy one a nurse, go ahead, but be a doctor if i.e. your dream
retirement
You could get the nursing amount and then travel back if you close to. If you want to be a practicing medical doctor (pediatrician), though, you'll need to run back for your M.D., not your Ph.D., which is more of a research-related level. If you really want to go all-out you could turn the M.D./Ph.D. route and get both, but if you do that I don't know how much time you'll enjoy to work the nursing job.
A Ph.D. program itself is pretty much a brief of its own. You should be paid a stipend to do research and edify undergraduate labs or courses. They often frown on you have any kind of outside duty. With the M.D. program, you could keep an outside position initially, but as you progress you'd probably have to quit the outside work. After your second year of medical arts school you start on some of the boards, then you step into clinical rotations starting your third year. I don't know how feasible it is to hold an outside position while doing all that.