[Sangetsu]

Even a school like Nova a lot of expense is made for new teachers. The biggest loss when a teacher quits suddenly is housing. A one year lease is signed, and if a teacher leaves early a large penalty is paid by the school.
Eventually a new teacher will fill in the spot, but the process takes up o 3 months. That said, I don't have much sympathy for Nova, but these new hires who jump ship as soon as they get to Japan are the reason why schools often require teachers to travel to japan at their own expense. The next new teacher who has to shell out a thousand dollars or so to start his/her job now knows who to thank.

As for work in Japan, there is a demand for nurses, but nurses in Japan earn much less money than their American counterparts. You will make as much or more by teaching English, and you will only have to teach 20-odd hours per week.