While it's certainly true that the processor's graphics engine has support for driving three DP monitor connections, this doesn't mean that a particular system can support three displays. My understanding is that, due to limitations in the USB-C connector implementation in the BN NUC design, only a single display can be driven by this connector. See Setting Up Multiple Displays for the Intel® NUC for more information.
Thanks for responding! I'd already looked at that link - it's where I had deduced the daisy-chaining of the 3x DP under the Triple Display Configurations section.
If what you're saying is true then it's not worth us investing in 3x DP monitors and appropriate cabling to even attempt this - seemingly monitors with the ability to daisy-chain DP are not as cheap as regular LED HDMI type monitors.