Yes, TORNILLO is a Scrabble word!

Letter values in Scrabble US: T 1, O 1, R 1, N 1, I 1, L 1, L 1, O 1.

Is it a valid word?

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

shrub or small tree of southwestern United States and northwestern Mexico having spirally twisted pods

Also: screw bean, screwbean mesquite, prosopis pubescens.