Hello Chris, thanks a lot for posting your issue at Intel Communities.
Regarding this behavior I was able to replicate the issue you are reporting. I went to the BIOS screen and I enabled UEFI shell. I tried to boot and I got the same black screen you mentioned.
I went to Windows, I restarted the system and before the NUC boots again, I was able to access the BIOS pressing F2 immediately.
I disabled that option and now my NUC is booting without problems.
In your case I would suggest you to try doing a BIOS recovery. Do you remember which BIOS version do you have installed on your NUC? It will be necessary to download the .BIO file into a thumb drive and reinstall that BIOS version into the system. This procedure will reset the BIOS setting on your NUC.
Then avoid enabling this setting again on BIOS.
I have same problem. I checked "Internal UEFI Shell". I tried BIOS recovery as you suggested but without success. After reboot still this screen with EFI shell appears and is not possible to use keyboard. It looks like my NUC is dead. Please help! I have NUC DN2820FYKH with fw version 0038 and I tried recovery with same version.