As user miep said in a comment to your question, she might have understood you as
Gibt’s was Neues bei dir?
»Nein« as an answer would then be fine.
The reason I assume this misunderstanding is that
Was ist Neues bei dir? (A bit better: Was ist neu bei dir?)
is not idiomatic in German.
Nobody I know (native speakers, of course) would say that.
It sounds like a literal translation of
What’s new with you?
but it doesn’t sound natural in German.
Instead, you could ask as mentioned above, or you could say:
Was gibt’s Neues (bei dir)?
“Was gibt’s Neues” assumes something new (“What’s new?”) while “Gibt’s was Neues” asks whether there are news or not (“Anything new?”).
One is answerable with yes / no, the other asks for more information.
But they’re used almost interchangeably.