simplynuc.com will sell turnkey NUCs complete with Win10-IoT for NUC generations as recent as 8 e.g., a NUC8i5BEK.
But, how can I install Win10-IoT on a bare NUC?
I found this Microsoft IoT guide that describes how to build a Win10-IoT image, but I'd need BSPs for the NUC and I'm not sure where to get them. Anyway, I'd guess that pre-built images would be available for NUCs.
If you purchase a NUC as a kit or a board, you are going to have to add memory and storage before you can install any software.
As for BSP files, I do not believe that Intel provides any. There is nothing about the 8th gen NUCs that would preclude their use (well, other than overkill).