I'm a fellow pack-a-day marlboro red smoker and occasional dxm drinker and, yes, nicotine absolutely fucking floors you regardless of how much you smoke. It's like smoking your first cigarette without coughing like a dickhead, my ashtray was full of ciggies with like 3-4 drags off them.
After I overdosed on dxm (probably should have gone to hospital 7 day trip overdosed) I swear it reset my nicotine tolerance (not addiction, just how much nicotine effected me), it was fucked- from pack-a-day to wanting to puke if I smoked 2-3 too quickly after one another...