Problem with second USB camera on Xavier NX

Please check if you can launch the camera by following the steps in Jetson Nano FAQ
Q: I have a USB camera. How can I lauch it on Jetson Nano?
The steps are valid for all Jetson platforms. You may try and see if you can launch the two cameras through gst-launch-1.0 commands.

And you can execute sudo jetson_clocks to get max performance.