You are certainly more than mathematically qualified; there would be no problem about work permits, I should have thought. Whether you would be hirable is largely a question of whether you have the right personality to control a class; you probably know the answer to that.
If yes, I would imagine you would be very hirable indeed as a teacher, particuarly in the independent sector where academic strength is seen as more desirable (and where formal teaching qualifications are not required). It’s likely that such a school would be willing to train you on the job and put you through the formal qualifications in your first year.
Certainly my own PhD and lecturing experience helped make me an attractive prospect to these kinds of schools.