I have a shiny new NUC7CJYH and a lot of problems with that box. It behaves weirdly with Ubuntu (see for example NUC7CJYH Linux/HDMI issues |Intel Communities). I'll likely end up installing WIndows on that box (Intel Linux support for new devices is spotty) but I also wanted to try something other than Ubuntu so I tried to run OpenELEC on that. Unfortunately that does not work at all. I have made USB flash media with LibreELEC USB-SD creator and latest OpenELEC version (8.2.4). Flash drive is recognized by NUC and I can boot from it but boot gets stuck at some point and never finishes. I do get "boot:" prompt and even can type a command there but after hitting Enter nothing happens at all (except that blinking cursor disappears). Nothing works after that, even Ctrl-Alt-Del is not doing anything, had to long-press Power button to turn it off. (see attach for screenshot).
I have also tried 8.2.0 image, and burning image to SD card, nothing helps, I observe exactly the same behavior. Tried to play with BIOS settings but no luck.