I have sent your case to my upper manager, I couldn’t confirm in our database if the NUC header has the option to turn it on/off from here.
I will be updating you as soon as possible.
For power on, a momentary contact switch connected between pins 14 and GND (pin 15 or 20) is necessary.
For reset, a momentary contact switch connected between pins 13 and GND (pin 15 or 20) is necessary.
Clear as mud?
P.S. It's too bad that pin 16 wasn't also a ground (GND). This would have allowed pairs 14-16 and 13-15 to be used for the two switches. I am sure there was some specific and valid reason why it wasn't done that way...