Thank you for posting in the Intel Community.
I see that you are looking for an external Graphics card to use with the Intel® NUC, in this case, you can refer to Intel® Product Compatibility Tool (http://compatibleproducts.intel.com/ProductDetails?activeModule=Intel%C2%AE%20NUC#) and search for Intel® NUC model you can search under the Thunderbolt™ and USB Type C Devices for information.
Hope this helps.
Intel Customer Support Technician
Under Contract to Intel Corporation