I started experimenting with nicotine gum as a non-smoker. From what I've read, the method you get your nicotine has a major effect on level of addiction. Inhalation combines a habitual act with the near instanaeous activation time to create a highly addictive behavioural habit.

I chew one 4mg piece of gum over the course of a day for mental stimulation and that's had some really nice side effects for me, such as being able to stay up later and continue on mentally engaging work.