Yes, TANSY is a Scrabble word!

Letter values in Scrabble US: T 1, A 1, N 1, S 1, Y 4.

Is it a valid word?

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

common perennial aromatic herb native to Eurasia having buttonlike yellow flower heads and bitter-tasting pinnate leaves sometimes used medicinally

Also: golden buttons, scented fern, tanacetum vulgare.