I am a nicotine lightweight so I can definitely sympathize.
I actually do not recommend Coke or Pepsi to counteract nic-sickness. Beverages with caffeine can actually intensify the sweating and nausea.
Instead, if you get to that point, stop smoking immediately and drink something like Sprite or 7UP - high in sugar, no caffeine. I have actually in the past just put a few teaspoons of white sugar in a juice glass of water and downed it.
In about 15 minutes the nausea goes away.