Alonso Tapia tells me that the most popular game is Carioca.
Other popular card games in Chile are Canasta, Poker and to some extent Bridge.
Games with Spanish Packs of 40 cards are also very popular: the most popular are Brisca and Escoba, played the same way as in Spain.
In the south, Truco is played, with somewhat different rules from those used in Argentina.
Also, Palitos is an exact trick-taking game, similar to Oh Hell!; it is sometimes known as Whist.
The World Casino Directory includes a listing of Casinos in Chile.