900 USD for SCL-LIM roundtrip in J doesn't sound crazy high actually.

Keep in mind that the "method" is just switching to the Chilean version of the site in the websites country selector (no need for TOR, VPNs or any other arcane magic).
Alternatively, you can just browse direct to https://www.latam.com/es_cl/

The real fare differences are noticeable on 100% domestic routes (for example, SCL-CCP could cost 70 USD roundtrip on the chilean site, 450 USD rountrip on an international site). On international routes to/from Chile, there may be differences, but they are not quite steep