I am also sure that many people realize this can be done but haven't really done it. IF your car is not a traction control car, you can use the traction control activation input to retard your timing by whatever amount you want. Just go into the tables in TC or LT1E and adjust how much retard you want at different RPM's. You can either install the bulb in the traction control location in your cluster or you can also use the traction control active output from the PCM to illuminate a light or LED to let you know the retard is active.

Another safety you can wire in is put a relay on the TC active output so the nitrous will only engage when the retard you put in your tables is activated.

If you did not realize you can do this, there you go. Any further explanation required? Feel free to ask.