Yes, KACHINAS is a Scrabble word!

Letter values in Scrabble US: K 5, A 1, C 3, H 4, I 1, N 1, A 1, S 1.

Is it a valid word?

KACHINAS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a masked dancer during a Pueblo religious ceremony who is thought to embody some particular spirit
a deified spirit of the Pueblo people
a carved doll wearing the costume of a particular Pueblo spirit; usually presented to a child as a gift