Yes, COATINGS is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, A 1, T 1, I 1, N 1, G 2, S 1.

Is it a valid word?

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

a thin layer covering something
a decorative texture or appearance of a surface (or the substance that gives it that appearance)
a heavy fabric suitable for coats
the work of applying something;