Supposed as case particle に(ni) + conjunctive particle て(te).[1][2]
An alternative analysis suggests that に(ni) may be a conjugation of an ancient copular or stativeverbぬ(nu), which persists in modern Japanese as particle に(ni) and auxiliary verbぬ(nu) / ず(zu). This would make nite appear to be a regular conjunctive conjugation of the copula. Compare the て form of Japanese verbs.