I went to the US State Dept website and checked. It says "...A Tourist Card will be issued for a stay of up to 90 days upon payment of a reciprocity fee, currently US $160. Currently, the fee is only charged at the Santiago International Airport. Payment can be made in U.S. currency or by credit card." If you transit through SCL to IPC I don't know if you have to pay it or not. Couldn't find anything about IPC.