It's open to any country - in fact, there should be local "chapters" in many countries. It's called NaNoWriMo because when it started ten years ago, it was only a few people. It's grown since then but they never changed the name.
I'm doing it this year. I'm not trying to have a complete work by the end of this month, just the first 50,000 words of a larger work (to be finished by the end of this year, hopefully).
and i guess i've known it all along / the truth is, you have to be soft to be strong