Previously I mentioned that I needed a high-side switch that the processor could control to enable +170VDC power to the Nixies when it was ready. I prototyped it 2 weeks ago, but it wasn't until today that OSHPark came back with the boards. I didn't make it breadboard-compatible, since it's just intended to be a little module.
It must have +170VDC to switch or else the voltage divider for the high-side MOSFET doesn't give the gate the right voltage. But then you can use 3v3 or 5v to turn it on.
Eagle and Gerber files in the Files section.