Yes, MOLE is a Scrabble word!

Letter values in Scrabble US: M 3, O 1, L 1, E 1.

Is it a valid word?

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

the molecular weight of a substance expressed in grams; the basic unit of amount of substance adopted under the Systeme International d'Unites
a spy who works against enemy espionage
spicy sauce often containing chocolate
a small congenital pigmented spot on the skin
a protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away
small velvety-furred burrowing mammal having small eyes and fossorial forefeet

Also: gram molecule.