Yes, MALTASES is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, L 1, T 1, A 1, S 1, E 1, S 1.

Is it a valid word?

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

a republic on the island of Malta in the Mediterranean; achieved independence from the United Kingdom in 1964
a strategically located island to the south of Sicily in the Mediterranean Sea

Also: republic of malta.

Not playable in Scrabble US: MALTA.