Trap speed is given by the integrating the power that is delivered by the engine over the period of time your car runs down the track. So while your NOS (spoolup) setup does not affect PEAK power (which is what you measure on the dyno), it will in theory increase trap speed because it increases part of your power curve. It MAY not affect it in a significant way since it is only for a short duration relative to the your ET, but I would not make any guesses until you try a run without the NOS...