Many people - including many health professionals - believe it is the nicotine in cigarettes which causes cancer. This is wrong. It is the toxins in cigarettes, released when tobacco is burned, which cause cancer.
There is no evidence that nicotine itself causes any short or long term harm, although people with heart problems should avoid any stimulant drug. And don’t forget, nicotine is the chemical in nicotine patches, gums and lozenges which are approved by medical authorities for long term use.