The nixie is running on 180v.
The 12v powers the arduino and nixie PSU.
The 5v is for chip logic (vcc input).
I have the nixie hooked up to the 180v + and the ten other nixie leads linked to the chip.
The chip has four logic pins coming from the arduin (5v), one 5v Vcc, ten nixie -ve connections and one ground connection.
I'd a tad confused - why would a nixie control chip not run at nixie voltages? Everything I read beforehand said I needed 120 - 180v to power a nixie.