Koze mande chez? I often ask Haitians about this expression and I usually get vague answers. Mandy how would best translate this in English?

Sometimes you may get 'vague'answers because there might be different uses for the expression you're looking to translate.
Trying not to be 'vague', I can tell you that this expression BASICALLY means let's sit and talk/debate on/reflect on ....

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words