[grzm]

While there are a lot of carcinogens associated with smoking, there doesn't seem to be a consensus that nicotine is one of them:

> Although there is insufficient evidence to classify nicotine as a carcinogen, there is an ongoing debate about whether it functions as a tumor promoter. In vitro studies have associated it with cancer, but carcinogenicity has not been demonstrated in vivo. There is inadequate research to demonstrate that nicotine is associated with cancer in humans, but there is evidence indicating possible oral, esophageal, or pancreatic cancer risks. Nicotine in the form of nicotine replacement products is less of a cancer risk than smoking. Nicotine replacement products have not been shown to be associated with cancer in the real world.

https://en.wikipedia.org/wiki/Nicotine#Cancer

The fact that it's other compounds that are carcinogenic rather than nicotine in no way changes the effects of second-hand smoke.