Indeed there must be something at that analog port to bring the range to 3.3V but I'm not sure what it is - a plain voltage divider sounds like a terrible idea to me, as the pretty low impedance needed for it not to mess up the analog port, messes up just about any input signal. Haven't seen any clear schematics, and the NodeMCU board is too dense to easily do trace following (and many components are unmarked anyway).
The input impedance of the analog port is supposed to be in the tune of 60M or so. Would require an OpAmp buffer or so.