Only really consider Argentina or São Paulo in Brazil mate. If you're gonna do Brazil, I'd suggest a coastal town with ex-pats that's far from civilisation or São Paulo as the only options. Peru, Chile, Ecuador and Bolivia are not bad options but living standards are lower everywhere other than Argentina in general.
Brazil (São Paulo especially) is known for its high surgical and medical standards. São Paulo state in general is heavily influenced by the native Tupi culture which you'll come across references to literally every 10 seconds or so.
Buenos Aires and São Paulo (and to a lesser extent Rio) offer some decent chances at working on the side as an English tutor or teacher. You can make USD$1000+ a week in São Paulo as a private teacher doing your own lessons, but that's relatively full time.