Direct Stream on Twitch with GStreamer

Not sure if Twitch supports RTMP. If it support RTMP, the pipeline looks OK. For trials, you can try videotestsrc and software encoder x264enc. Once you have constructed a working pipeline, you can replace with real source v4l2src and hardware encoder nvv4l2h264enc.

If Twitch supports RTSP, you can try
Jetson Nano FAQ
[Q: Is there any example of running RTSP streaming?]