> which is what Nigeria actually wants
Declared by who? And that politically correct statement is believed by who? (other than you)
> no reason
??? Doctor training is one of the Top heavily subsidized by the state. (As with weapons. but no one is chanting "Weapons Weapons Weapons" but "Doctors Doctors Doctors" because PC, as zelensky the clown has found out the hard way even for a christian country.) Sure, it's expensive to subsidize the capital for a literature major to sit in a beautiful airconditioned classroom with a courtyard.. at least until you find out the annual mortgage of a PBT facility.
Tldr use common sense. If every doctor I export out of the country gets me 4.48b cf js.do/code/740428 (prepaid btw, for the correct interest rate to charge does not make any sense considering the country may not be around for another 99y), then I only need to export 100 per year [out of 220M] to twice my gdp; heck you'd do it all day long every single day.
It absolutely is the issue, because Nigeria has a shortage of doctors. It has nothing to do with whether or not Nigerian doctors send money back home. If they send lots of money back home, they still aren't in Nigeria practicing medicine, which is what Nigeria actually wants.
If this was about money then there'd be no reason to make a law specific to doctors, as many other Nigerians emigrate for better economic prospects elsewhere.