Yes, CHIMAERAS is a Scrabble word!

Letter values in Scrabble US: C 3, H 4, I 1, M 3, A 1, E 1, R 1, A 1, S 1.

Is it a valid word?

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

(Greek mythology) fire-breathing female monster with a lion's head and a goat's body and a serpent's tail; daughter of Typhon
a grotesque product of the imagination
a deep-sea fish with a tapering body, smooth skin, and long threadlike tail