Sorry y'all for the delay. Offline life threw some zingers at me. Anyhow, here is what I did to upgrade my Nvidia Shield tablet (RoW LTE) from Marshammlow to Nougat and then install Kali Nethunter.
1. Make a nandroid backup. REALLY!
2. Find an AOSP Nougat ROM you like & throw it on your SD card.
3. Download your Gapps & Superuser. I'm using the Pico Open Gapps & Chainfire's su version 2.52.
4. Boot to Recovery & wipe.
5. Flash the ROM, Gapps, & su.
6. Wipe caches. Reboot.
7. Let your ROM settle & set things up a bit. Mainly here you just do NOT want to flash the new kernel on a "clean" setup.
8. I pulled the kernel from here:https://www.securityaddicted.com/201...shield-tablet/
(A big thank you to Alex!)
9. And the latest Kali Nethunter rolling generic.
10. Reboot to Recovery.
11. Make a nandroid backup.
12. Flash Nethunter.
13. Flash the kernel.
14. Reboot the most awesome tablet ever!
15. Open your Nethunter app as usual & finish the setup, install chroot (f needed), etc.