Transferring Nandroid Backup between two devices I did a Nandroid backup via ClockworkMod Recovery on my NVIDIA Shield, and want to restore it onto another NVIDIA Shield (due to the recent recall). Is it safe to restore the Nandroid backup onto another device of the same type? If not, is there any way to modify the backup to allow me to do this?
Restore only /data, /system, /boot (and optionally, /cache). Advanced Restore option in CWM recovery should allow you which partitions to  restore. Otherwise, Philz Touch Recovery (fork of CWM) has this option. 

I'm choosing only selected partitions because if your device has concept of EFS then you may end up with IMEI trouble. 

Note that while restoring make sure that the rest of firmware on both the identical models is same (modem, uboot and more). It should be same if they are running the same Android build. Otherwise, it is very likely that you may end up with a soft-bricked device at the least.

Also, make sure that the both  the devices are fully  backed up so that you don't end up with data loss at least.