In Pucon, check out Nathan's deal above. He's got a pretty cool set up and a lot of knowledge about the rivers in Chile and Argentina.
If you are further north, we are out of Curico, 3 hours south of Santiago on the Rio Teno and Rio Claro in the small mountain town of Los Quenes. We provide instructional based trips, drivers, shuttles, rental vehicles, and beta. Many boaters come through looking to hook up with boating partners.
For more info-