Aeromexico, a SkyTeam member airline, have round trip airfares travelling from Los Angeles (LAX) to Santiago Argentina (SCL) for $569, making 1 stop in Mexico City for several hours.
Departs LAX: April - November 2019
Unfortunately google flights doesn't show dates for Aeromexico until you click on specific dates. I tested dates and it looks like their promotion runs in the Summer. Trial and error on your dates and see what comes up for you.
To book this, use Skyscanner [skyscanner.com]
or Aeromexico [aeromexico.com]
Santiago Chile Travel Guide [skyscanner.com]
. Want to see more travel deals? Click here or here.