Yes, KNISHES is a Scrabble word!

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

Is it a valid word?

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

(Yiddish) a baked or fried turnover filled with potato or meat or cheese; often eaten as a snack