Chaya is meant to be a hot girl and thus often adopted by young girls referring to themselves.
Unfortunately it is an orthographic mistake, hence the word correctly spells Tschaia or Tschaie, which originates from a whole set of 'moving languages' (Read gypsiy slang et al) and means plainly a girl.
Hence those languages are mostly spoken languages, it is usually hard to define the correct orthography, yet the transformation into chaya might be related to spanish (that certain latin(a/o) touch) or just shows the typical social lower class educational level.
Diker ma die Tschaia (Chaya), die tscheft gar tschie tschuggern.
Translates roughly to:
Check out that chick/girl, she ain't nice at all.