Yes, NYMPHALIDS is a Scrabble word!

Letter values in Scrabble US: N 1, Y 4, M 3, P 3, H 4, A 1, L 1, I 1, D 2, S 1.

Is it a valid word?

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

medium to large butterflies found worldwide typically having brightly colored wings and much-reduced nonfunctional forelegs carried folded on the breast

Also: nymphalid butterfly, brush-footed butterfly, four-footed butterfly.