Generally ÑERI is not a word used in Argentina. Maybe in any place it could be a kind of slang that I really don't know.
I'm trying to think something else about it and ÑERI could be used to express these words COMPAÑERO or COMPAÑERA (male or female). As a result ÑERI does not have gender in order to talk with a man or a woman. This is only an opinion, I don´t know how to use this word.
If you want to say friend in Spanish, talking to people from Argentina, just say AMIGO o AMIGA.
If you say ÑERI, in my opinion only a few people could understand it.