The issue is not much being a citizen of the country you want to fly in, most South American country allow expats, I think Brazil is the only one with very strict rules. The problem is that often you need to be a legal resident before you can apply for a job or even get the license conversion. Even as a Mercosur citizen you need to some degree apply to a resident/work permit.
I fly in Suriname and we have many expats here.
Try your luck in Guyana.