I'm confused are you spraying a dry shot after the MAF and before the TB
If so your computer not going to make the necessary fuel adjustments.
OK I JUST READ WHERE THE TB AND MAF ON THE 3800 v-6 ARE INTEGRATED
If you're spraying the Nitrous directly on the MAF you may damage the sensors filament or throw off it'* readings.
For this application the nitrous nozzle would have to be carefully aimed so as to completely miss the sensors filament, ideally being installed in the MAF meter itself on the opposite side of the filament.
I hope that this helps.[/b]