Withdrawal for tobacco is basically mild discomfort. It can't be in the same class as drugs that cause seizures, profuse sweating, and death upon immediate cessation.
Depends what you mean by mild. For me, going cold turkey from nicotine was migraines, severe anxiety, irritability, and fatigue. Not life threatening, but I was unable to function. That said, tapering off with a controlled time-release dosage (patches) was sufficient to reduce it to actual mild discomfort for me.