From this thread I don't know what is your hardware configuration, but from the other thread you have posted, I saw that you are deploying some 50 NUCs, so, probably you know what you are doing and there is some problem is specific NUC. Any way I'll try to give you some idea, that may be helpful.
1. Are you using wireless keyboard? If yes, try to insert the receiver in other USB slot.
2. Is this keyboard functional in other computer?
3. If you are using wireless keyboard, can you try a wired keyboard?
4. Try to recover your Bios using Security Jumper removed method (i.e. boot your computer with security jumper removed and with USB stick formatted to FAT32 and bios file *.bio). The recovery shall start automatically without user intervention.
5. Can you install Windows?
You are right about the other thread. I opened this thread because i want to clear the TPM by removing the Security Jumper, wich is now impossible because the keyboard isn't working.
Other keyboards from other vendors aren't working either.
The keyboard itself is working perfectly in other computer.
I tried earlier to recover the bios with the same method you described.
Deploying the OS is no problem at all, except enabling Bitlocker.
If you can deploy Windows, try to boot into Advanced Menu. From Advanced Menu you can boot into UEFI BIOS. In bios you can reset the bios to default settings. This may be will fix the keyboard problem.
The quastion is if the keyboard is functionable in Windows or during Windows installation?