My thoughts: Welcome to the United States of Corporations. You're screwed.
Insurance companies test for contanine, usually by urinalysis, because it's cheaper than a blood test.
If they do a urinalysis, then find a way to cheat. I would claim I don't smoke, because you don't. Then, put the money aside in case they test you in the future and stick you with back payments. More likely though, is the formal question will be "Do you use tobacco?"
Insurance companies aren't interested in nuance. They detect the presence of a metabolite of nicotine. They don't care how it got there. If you tell them you're using a patch or chewing nicorette, they'll tell you to come back in 6 months or a year when your course of cessation therapy is over and you're nicotine free.
In fairness to your insurance company, it's your employer who is the biggest sleazeball involved. Group health plans don't individually assess employees for smoking. They don't assess them for snow-skiing, alcohol drinkin, motorcycle riding or parachuting either. Your employer has taken it upon himself to impose a sin tax on his employees and he's a lowlife of the highest order. If you didn't live in a state suffering from a fascist government, I'd say sue his brains out. But, I'm sure your Governor has seen to it that your employer has free rein to treat you like the feudal serf he envisions you to be.
Find another job. That's your best course of action.