This article explains why it is not possible to power an Intel® NUC Kit through Thunderbolt™ from a docking station.
Can you power an Intel® NUC Kit using Thunderbolt™ port via a docking station, instead of using its own external power supply?
Intel NUC Kits aren't designed to be powered via USB-C.
The Technical Product Specification specifies the Thunderbolt charging capabilities is only up to 5 volts, which isn't enough for the Intel NUC Kit to function. By design, the board should be powered through the 12-19 V DC connector on the back panel.