There is no 'standard' wheel pressure. You pick a pressure, run a few laps, measure tire temps and adjust pressures accordingly.

I mean, if you're doing this (nitrogen) for the best performance then do it right.

 

For a street driven car, set your tire pressure just as the OEM recommendation - 28psi. If you want to be safe, 30 or maybe 32psi will also work.

Generally speaking the tire pressure recommendation is based on vehicle weight. That does not change when you change wheel/tire size.

Dave