Hi nbeser1,
It is expected since there’s QSPI in the module including the bootloader and several partitions so that you have to flash each module once.
You can refer to Orin Nano QSPI Flash Only - #4 by KevinFFF to flash QSPI only for the Orin Nano devkit.
You can also refer to Workflow 7: Initrd Massflash in <Linux_for_Tegra>/tools/kernel_flash/README_initrd_flash.txt for your use case to flash multiple devices.