From the Jetson Nano getting started, it leads to this link:
That link redirects to this:
Note the name contains
jp461, but in fact there’s a JetPack 4.6.3. Note the name also contains `r32_Release_v7.1, but L4T is up to 32.7.3 (see here).
I’m not sure where all the SD card image files are archived.