Yes, NORMALIZING is a Scrabble word!

Letter values in Scrabble US: N 1, O 1, R 1, M 3, A 1, L 1, I 1, Z 10, I 1, N 1, G 2.

Is it a valid word?

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

become normal or return to its normal state
make normal or cause to conform to a norm or standard
bring to a desired consistency, texture, or hardness by a process of gradually heating and cooling

Not playable in Scrabble US: RENORMALIZE, RENORMALISE.