Yes, TESLA is a Scrabble word!

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

Is it a valid word?

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

a unit of magnetic flux density equal to one weber per square meter
United States electrical engineer and inventor (born in Croatia but of Serbian descent) who discovered the principles of alternating currents and developed the first alternating-current induction motor and the Tesla coil and several forms of oscillators (1856-1943)

Also: nikola tesla.