The nursing science courses are generally not equivalent in rigor. The medical model vs the nursing model is very different; some of the most difficult students I've had have been nurses previously: they tend to have a "been there done that, know it all" attitude when nothing could be farther from the truth.
It's a good fall back career if med school doesn't pan out but I can't suggest it as a good background for medical school. I believe it's changing somewhat but I think there is still a stigma against nurses who leave the profession to go to medical school. There are several users here who have been in that position and could speak to it better than I.
You are right WS in that some nurses can be "been there done that, know it all," but it's certainly not true for all of us. Kind of makes me feel sad that you feel that way, but you know what your experiences have been.
Some nurses are just plain scary with that attitude; but the good ones always have the sense to know that there's a lot that they may not or do not know, and they always put the patients first in that regard. In nursing, there can sometimes be this anti-surgeon mentality. As a surgical recovery nurse, however, I have very much enjoyed working with surgeons. I think there can be very good give and take in the work relationship, if people care about making an effort. But there are some nurses that don't realize that they really have to prove to the surgeons that they know how to look out for the patient, and that they know when they really need to let the them know what's going on w/o being an idiot about calling over stupid things. My experience has been that once a surgeon believes you have enough sense to follow within your scope and do the safest thing for the patient and follow their directions, then they are fine with you.
Also, I really think that some nurses, at least early on, don't understand what a physician has to go through to become a surgeon. If they stood back and paid more attention, they'd get why the surgeons are of so particular when it comes to their patients. I have learned so much from surgeons--primarily about how patients should be managed post-operatively. As an SICU recovery nurse, it's good to know what the surgeon has done and what the plan/goals are from their POV. I am there more to be a set of eyes and ears, etc for their patients post-operatively when they can't be there. They are often juggling so much at once it's mindboggling. So you can't bug them for idiotic things, but you sure as heck better know when to contact them over the important concerns.
Not too long ago, I had to talk with a nurse re: the fact that she was whining about being busy (having trouble drawing some labs and other things), and she was miffed b/c the surgical resident commented about the last hour vitals, hemodymamics, ABGs, labs, infusions, CT drainage, and I&O's not being there on the flow sheet. What I had to help her understand was that surgeon must have the necessary data up-to-date and be in the OR all before 0700. It astonished me that she didn't understand all that needed to be completed by him by 0600. But sometimes nurses just don't even try to understand the other side of things, so they mouth off without thinking.
As far as the sciences, well, truly it depends on the school. Some school's nursing programs require the same general bio or chem, whilst others have less robust science courses for nursing students.
I don't know if it is a good background for medical school. Some nurses, who are now physicians, say yes, and others say no. In the end, I really think it depends upon the nurse and her/his individual, professional experiences and clinical exposure.
ITA that it's probably not the best major to go for if you KNOW you want to pursue medicine. To me, a better undergrad choice might be something like biochemistry. If I had it to do all over again, that's what I would go for, but I really wasn't seeking to go any other path but nursing when I studied nursing. I think biochem would be a great program of study. Either that, or I would consider microbiology; b/c for some reason, I really got into general microbiology.
So, WS, I am wondering how many med students/former nurses with whom you have interacted as med students were post-surg recovery nurses, and if that made a difference? I did a lot of CTICU/OHS recovery. Let me tell you, nurses that seem to be a little too know it all, well, they slap that right out of you. LOL. The CT surgeons pretty much make it clear what they expect, b/c the really good ones usually run a tight ship. You gotta want to play on their team, and they are the coaches. LOL. They do a lot of quarterbacking too.