Hi athreya.rajaraman,
Do you connect the external NVMe SSD on the Orin Nano devkit?
If so, please run the following command to flash your devkit.
$ sudo ADDITIONAL_DTB_OVERLAY_OPT="BootOrderNvme.dtbo" ./tools/kernel_flash/l4t_initrd_flash.sh --external-device nvme0n1p1 -c tools/kernel_flash/flash_l4t_t234_nvme.xml -p "-c bootloader/generic/cfg/flash_t234_qspi.xml" --showlogs --network usb0 jetson-orin-nano-devkit internal
You can also try if the following command working in your case.
$ sudo ./flash.sh jetson-orin-nano-devkit-nvme internal