Yes, PALETTE is a Scrabble word!

Letter values in Scrabble US: P 3, A 1, L 1, E 1, T 1, T 1, E 1.

Is it a valid word?

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

the range of colour characteristic of a particular artist or painting or school of art
board that provides a flat surface on which artists mix paints and the range of colors used
one of the rounded armor plates at the armpits of a suit of armor