I understand you are facing some issues with the resolution of your NUC. Allow me to help you regarding this issue you are facing.
In order to help you better, I would like to gather more information about the configuration you have on the computer. Please attach to this thread the TXT file the Intel® System Support Utility will generate: https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility
To attach a file, you must click the "Attach" option on the bottom right-hand corner of the response box.
I would like to know as well which type of cable you are using to connect the NUC to the display and the model of the display.