As someone with a reasonable amount of experience working with people (and originally for myself) seeking to quit self-destructive habits, I'd state that the Chantix (aka - wellbutrin etc) is an excellent assist since it cuts down on the physical withdrawal symptoms experienced when a habitual nicotine user reduces intake.
But an equally important component is a determination to No Longer Use.
That sounds simplistic, I know. But it's demonstrated by some fairly deliberate actions like, no longer buying cigarettes, or maybe no longer carrying cigarettes with you wherever you go.
By either ceasing or severely cutting back acquistion of cigarettes, you obviously reduce supply and increase the odds you will not have one handy when you engage in the long established habit of reaching for one.
You will find it an interesting step in the recovery process as you may well be surprised as to how habitual just buying cigarettes is for you.
And by leaving them at home (for example), you will also find that while at work or in other away from home venues a renewed "strength" found simply because as you reach for a cig, you do not have any in your pocket....or purse, or briefcase, or desk drawer, or automobile console, or bathroom drawer or kitchen drawer of kitchen table or back porch table or (perhaps most important for most tobacco users I've met) your bedroom nightstand.
Eliminating that last 60 to 90 minutes before you sleep and that first 60 minutes when you wake up will greatly increase your odds of "clean time". Which for a tobacco user is often measured in minutes/hours rather than "days" as you reduce and eventually eliminate the habit.