Kim Kardashian -- Nephew Mason Breaks the Mold and Talks!

Kim Kardashian assumed auntie duties in Calabasas Tuesday ... taking her nephew Mason Disick to the movies.

Kim didn't have a lot to say but Mason did. He told our photog he went to see "Teenage Mutant Ninja Turtles" in The Commons. He also has a fav -- Donatello.

We're told Kim took Mason out for the afternoon so he didn't go stir crazy in the Montage hotel in Bev Hills, where mommy Kourtney, Daddy Scott and sister Penelope are staying because they claim the house they bought from Keyshawn Johnson is full of dangerous black mold.