Here's the SCL scoop. The lounge is available only in the secured departure area. Once you clear immigration it is TOO LATE. This is despite a detailed email from Lan prior to a trip in 12/01 in response to my inquiry - when they told me to get my luggage first, etc... If you are connecting to another int'l departure you are fine.
The national flight side has Pacific Club Salon VIP (not too far past security). Entry is approx. CL$10.000 or $11.000. They are currently Diners Club affiliated, but that comes and goes. Certain other credit cards get you in from time to time, but each trip, its a different story. In any event they have a shower room which is spartan but clean, no hair dryer, etc. Free drinks but no snacks to speak of.
They are also Priority Pass associated, but if you are on a pay per visit PP membership, the PP fee is higher than the actual fee if you just pay there.
Pacific Clubs Salones VIP have a network of lounges around various airports in Chile. I have been in 3 or so of them. They all have dialup internet terminals, free drinks, and your snack is "nuts with raisins." You can also buy a membership for a single lounge, or multi city access.
While they are nice and peaceful and quiet, so are most departure areas in most airports in Chile most of the time. ¿Vale la tarifa? A veces.
I provide all this info because despite my previous FT inquiries, and no one having any good info, I learned it on my own.
Suerte