Yes, MANIOCA is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, N 1, I 1, O 1, C 3, A 1.

Is it a valid word?

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

a starch made by leaching and drying the root of the cassava plant; the source of tapioca; a staple food in the tropics

Also: cassava starch.