I live in Taiwan which has National Health Insurance which I am enrolled in. We are issued a health insurance card and I have a residents visa. I also maintain a mailing address in the USA basically for IRS and banking.

The question I see will be if the IRS will accept documents from a country the USA does not even recognize?

If I visit the USA will I have to provide proof of insurance if I stay more than one month?

Are they going to cross check that against my passport entry/exit?