They are nicotine delivery devices, as are cigarettes, pipes, the patch, the gum, etc. They are a method of delivering nicotine into the body. It was by classifying cigarettes/chew/etc as nicotine delivery devices that the FDA was able to gain control over the tobacco business. (
Tobacco Advertising; Children and Tobacco; Executive Summary)
What you are thinking of is medical device (which is what the FDA was trying to classify them as).
79, 80, and 81 are all links to references at the bottom of the page. All three go to different lists of studies and resources on CASAA's page.