To say "hello" in some of the major Naga languages, you would say:
* Ao: Akübo
* Angami: Akübo
* Lotha: Akhübo
* Sumi: Akübo
* Zeliang: Akübo
These are all very similar as they come from the same Tibeto-Burman language family.
If you let me know which specific Naga language you're interested in, I can give you a more accurate greeting!