Hi,
Please share what command you are running so that we can check and suggest next. For Orin Nano we use software encoder x264enc and you can see the code in the samples:
/opt/nvidia/deepstream/deepstream6.3/sources/apps/sample_apps$ grep x264enc ./ -r
./deepstream-dewarper-test/deepstream_dewarper_test.c: h264enc = gst_element_factory_make ("x264enc" ,"x264enc");
./deepstream-testsr/deepstream_test_sr_app.c: gst_element_factory_make ("x264enc", "encoder-post-osd");