An English teaching job: impossible?

Just read a bit more.

If your end goal is nursing, why think of teaching at all? If your goal is just Japan, you really need to think long and hard about why. If you haven't, I suggest trying to go on a holiday there first or try and get a temporary (couple of months) job there first, so you can see what you think of the country.

Before thinking of language schools, I also recommend getting some Japanese learning apps and maybe a textbook like genki. It doesn't hurt to study now, and if you want to be a nurse in Japan, you'll need high level language skills, so the sooner you start studying, the better.