Should an NCP3420 Draw Minimal Current with Only VCC and GND
Yes, assuming you have Vcc and GND hooked up as shown and they are the correct polarity and voltage (as you say they are) the part is likely broken and not meeting the datasheet spec:



Regardless of the state of the output enable, if the output is disconnected the part should draw no more than about 6mA. The datasheet condition specifies that the BST voltage is 12V, but I don't believe that can make the current any lower than spec, likely the reverse.

You might try grounding the logic inputs on the off chance that the part is oscillating and drawing excess current.  (It's never a good idea to leave high impedance inputs floating.)