I was addicted to chewing tobacco throughout my life, since I was in my late teens, nearly 20 years ago. Recently (Jan. 4th) I decided to go cold turkey, the only thing that seemed to help was regular chewing gum and keeping myself distracted when the cravings hit the hardest. I chose mint flavored gum because it was the closest in flavor to my favorite type of tobacco. Another thing that I did was to quit during a time when I knew I would be away from a stressful daily routine (time off after the holidays). Maybe quiting on your days off from work or time off during a hectic schedule could be easier, instead of trying to quit during a busy week, might be less stressful for you (?).
Best of luck to you!
I'm not sure about the length for a Nicorette addiction, but I can't imagine it taking any longer then a regular smoking addiction which is 72 hours.
A good place to start is whyquit.com
Your addiction is still to nicotine so I'm sure that any of the articles there will apply to your problem, just replace cig with gum.
Good luck and we are a good place for support should you need it : )