Am attempting to wire a bath room fan with a light and night light to a 3 swtch control . If I use 12-3romex I still need an extra wire from fan to switch ? Or light to switch ? Unit is a nutone model qtn80l switch is leviton no. 1755 help! Also it appears I need to use the white wire from switch to blue wire on light or black wire to fan? Also power source is 12-2 romex to the fixture.

Assume you mean you want install switches to control the fan, the light and the night light individually, not that you are installing a set of 3-way switches.

Use 12-4 cable between the fixture and the switches. Color both ends of the white wire of that cable with black marker to designate it a hot. Use the white redesiginated hot to take power to the switch. Use red, black and blue to return power from switches to fan/light/nite light.

Home Depot sells a cable they call 12-2-2, could also use that.