I took note that Jetson Orin Nano no longer supports hardware based encoding (unfortunately I had to learn it the hard way after buying two Orin Nanos as follow up for my Nano based transcoding projects).
Nevertheless, the Jetpack images for Orin Nano still contain nvv4l2h264enc and nvv4l2h265enc and e.g. the deepstream-app automatically chooses these encoders, when you define a sink of RTSP type.
So from software side nothing prevents you from using these encoder libraries. The result is, that - if you are lucky - the software terminates with an error message that memory could not be allocated. But in most cases your Orin Nano simply freezes and after some time hard reboots (propably due to some kind of watchdog).
You can simply reproduce that using this test pipeline
gst-launch-1.0 videotestsrc ! nvvidconv ! nvv4l2h264enc bitrate=5000000 insert-sps-pps=true ! h264parse ! mpegtsmux ! rtpmp2tpay ! udpsink host=127.0.0.1 port=5000 sync=false