It looks like the Pacific Club is open 24 hours. It is a Diners Club and Priority Pass lounge. It is probably pretty spartan (I've only been in the Pacific Clubs on the domestic side, in PUQ and PMC). I don't know the cash charge, but I think it is about US$20 if you don't otherwise have access.
Airport: santiago - C. Arturo Merino-Benitez International, International Terminal
Lounge: salones vip pacific club
Location: Airside - go through Passport Control and Security. The Lounge is located in front of Gate 18.
Opening Hours: 24 hours daily.