Thank you for contacting Intel® technical support. I will be more than happy to help you.
I understand that you want to know if you are able to achieve a resolution of 3440 x 1440 @ 100 Hz via HDMI® or Thunderbolt™ 3 with an Intel® NUC Kit NUC7i7BNH.
If you use a straight connection with HDMI® 2.0 or Thunderbolt™ 3, you should have enough bandwidth to achieve that resolution with that refresh rate.
I can confirm that my Samsung C34F791 is working at its native 3440x1440 resolution at 100 Hz, when connected to NUC7i7BNH Thunderbolt 3 port via a USB-C to DisplayPort cable.
However, I was unable to use HDMI 2.0 with the same refresh rate. Not sure if this is possible.
Hope this information will help fellow NUC owners.