The section you posted is not supported on Xavier/NX because the cboot on rel-32.5 does not support NVMe. Need to wait for rel-32.6.
My post here explains the difference between “boot from” and “mount file system”.
Mounting file system supports on every rel-32 based platform. If kernel is able to read your nvme drive after boots up, then it can mount the file system from it. However, cboot does not.