At 3600 ft my MAP reading is only 85-90 kpa. And the pcm for less tune only advances the timing at 100kpa. So if I hit the nitrous , will the Map reading go into 100kpa, because of the best possible air in the intake?

I want to use a 150 shot ,but i hear that i might not want as much timing with this shot. I just want to make sure ,before I go blowing stuff up.