From 'Devices' in the connection menu it is possible to see the desktop's camera in the list of connected devices on the remote/local desktop and forward the camera from remote to local or vice-versa, but the camera cannot be used.

An example on how to reproduce:

1) connect to remote Linux desktop
2) open the connection menu -> Devices -> configure USB forwarding from remote to local
3) open the video application on the connecting Mac client and you get a black screen instead of the view

Reproduced on:

    Client: OS X 10.10.5, nx-5.1.33
    Server: nx-5.1.33, Ubuntu 15.10