You can connect the Dahua NVR to any ONVIF/RTSP-stream.
So, as long as the camera support ONVIF/RTSP you're fine.
I do this myself for a couple of cheap crappy ONVIF-cameras I have in the stable.
The downside is that you loose a lot of the benefits (features/intelligence) you'd have with a Dahua NVR+Dahua Camera Setup.