Yes, NECROPSIES is a Scrabble word!

Letter values in Scrabble US: N 1, E 1, C 3, R 1, O 1, P 3, S 1, I 1, E 1, S 1.

Is it a valid word?

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

an examination and dissection of a dead body to determine cause of death or the changes produced by disease

Also: post-mortem, postmortem examination, post-mortem examination.

Not playable in Scrabble US: PM.