1. Do you have some other operation system currently installed on on your NUC SSD ?
2. If you have already disk partition it is EFI or Legacy BIOS?
2. Is your SSD recognized in BIOS?
3. Please enter to BIOS setting and set it to default (press F9).
4. Disable legacy boot mode.
5. Verify in Devices->Sata that the Chipset SATA Mode is set to AHCI.
Your second number two was the key to success. unpowered and unplugged all connections to my new NUC then had another look at the newly installed SSD. I had not quite homed it into its slot. Therefore, it was not recognised in the BIOS (ie not connected at all!)
All good now. Successfully installed Linux Mint 18 _Sarah_
Thanks once again.