Both the Spanish nieve and the English for the same, snow, come from the same root, although via very different routes.
In Proto-Indo-European, the ancient ancestor to both Spanish (PIE turned into Latin then Spanish) and English (PIE also turned into ancient Germanic then English), the Proto-Indo-European *sniegwh for snow gave rise to both the Latin nivis — which turned into the Spanish nieve — and the old German sneo which became the English snow.
Thus, the n-v of nieve maps exactly to the n-w of snow. The key sound change, which is what can confuse us, is the loss of the initial s- as the word transformed from PIE into Latin and then Spanish.
