Gstreamer stop diffusing after 2 hours (Jetson nano 4GB)

Please try the command and see if it works well in long-run test:

$ gst-launch-1.0 v4l2src device=/dev/video0 ! videoconvert ! queue ! xvimagesink sync=0

See if camera preview is alive after 12+ or 24+ hour run. This can ensure the camera source is stable and does not trigger the issue.

And we suggest enabled the properties for streaming:
Encoding CSI camera with x264enc codec - #3 by DaneLLL