This message was posted on behalf of Intel Corporation
Thank you for posting on the Intel(R) Communities!
I understand you would like to find out if a daisy chain configuration can be achieved (Two Displays at 4K@60Hz)
I would be more than glad to clarify that matter to you!
This is something related to bandwidth, each link or video port has certain bandwidth available as well as the graphics adapter of your Intel® NUC Kit NUC6i7KYK. So in the case where the resolutions together do not overcome the bandwidth available, they can be achieved.
In this case, the bandwidth used for two 3840x2160 @60Hz would be 32Gbps which overcomes the 21.6Gbps available to be used.
For that reason, the current configuration where the two displays are 4K @30Hz is normal and 4K @60Hz cannot be done.
Here I add the place where this information was taken: page 37: http://intel.ly/2fuhB4T
and a screenshot of the information used (attached).
MST calculation.png 217.8 K