The requirements for LAN Chile are:
Chilean Commercial license with IFR by the DGAC
First class medical by MAE
English test ICAO level 4 minimum
Flightlog certified by the DGAC
They won't convalidate your commercial license. You'll have to get your license the old fashion way, written tests, oral and practical tests.
The medical is pretty extensive if it's your first time.
English test is a not difficult but expensive.
Flightlog certification is just paperwork.
All in all, you'll spend between USD$2.000 and USD$3.000. and give yourself 5 weeks maybe a little more.
Good Luck.
Y.