The nest gets its power from your furnace it will only be the voltage put out from your circuit board, usually 5 volts. It does not require power from a receptacle. You need to confirm that your furnace is compatible with your nest first using their online comparability chart.
The screw driver, screws and a large flat trim plate that is colored white is in the box. It does not match the thermostat but does not clash either. It’s a neutral white. There is a metallic colored one that will match the thermostat for sale if you want to match it