According to EVGA, my Nex750B Supernova does support 8pin and has a built in EPS12V 4+4 Pin with a +12v Rail of +12V1.
It also has another EPS12V 4+4 Pin labeled CPU 2 included but attached separately. This one has a +12V Rail of +12V3.
Both these cords seem to have two 4 pin connectors...