I don't like to judge people by their country. I don't think this is actually a good idea.
Poker is really a kind of strategy game mixed with a little bit of luck, and, as all strategy game requires, You can't underestimate or assume things about your opponents without having a good reason to do this, because this can lead you to your own fall.
I understand that each country and region of the world has different cultures, and you can try to use this to read your opponent. This happens everyday when we are talking about soccer, for example, as counties like Brazil, Italy and
germany won 13 World Cup together; the soccer culture is big and growing up every day at these places. At poker you can try to do the same; United States has a long term poker culture, and we are not able to say the same about Brazil, for example (as we are starting to grow up this culture by the last decades).
But, as I said before, I don't recommend to do this; I don't think this is the best way to know your villain (but, at the moment, if this is the best way you have to read a new player who just entered at the table and is playing his first hand... use this, of course!).