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.
