Well the Ogawa thing was okay, in that she says as much in IFM that her being made an MD was a formality: Starfleet's medical training policies during the Dominion War made MD training and advanced nursing programs interchangeable. Presumably Ogawa had something like an MSN plus even a DNP equivalent as head nurse of the Enterprise-E and Titan. If she also had accreditation for stuff like as a nurse practitioner or the like, I can see how it might be possible. Not entirely plausible, mind you, but by the time of IFM she's been a nurse on a frontline starship for 20 years. That's long enough to have gone through some advanced nursing degree programs, which, during wartime, might have also been similar to a medical residency.