How to power Nodemcu using 12 volt AC to DC adapter?
You connect the + side of the adapter to VIN pin and the - side to GND.
You have to check the maximum voltage when using the VIN pin. Probably it means you 'waste' some power (but it's from a wall wart, so it should be ok). See the remark of Flyingfenix below for heating consequences.
See this link: Power Related ESP-12E Development Board Pins, fragment 'Using a Wall Wart':

The current (1.5A) should be more than enough; the adapter's current should be higher than what is needed by the NodeMCU + circuit. So this is ok.