This English sentence is not correct. It should be, "No one is saying anything here."
English translation is unnatural, it should be 'no one is saying anything here'
This was very unnatural. It took me a while to figure out what word order duo wanted.
So in this sentence the koi corresponds to nobody and the kuch to nothing? Both made negative by the nahi?
Well, कोई means someone (as कुछ means something) so as Daniel712264 suggests the नहीं must serve to negate both in this sentence.
Only if this is a room of deaf people using sign language can this sentence be correct in English. Then the people are not speaking anything, but rather they are signing.
No, even then, it would be "No one is speaking," though they might be saying something.