I think we're going to talk. There's always the possibility it's a posed picture, though I doubt it. I'm going to want to do a whiz quiz unless there's a confession. I'm going to point out that addiction, to any substance, is a disease, and part of that disease is lying (to yourself and/or others) about your use. It isn't a matter of "not trusting him", but of caring too much about him to allow him to physically hurt himself.
If the whiz quiz is positive, we're going to talk about whether he wants to stop and can't, or whether he's just blowing me off. If it's the former, I'll get professional help, and will continue to monitor his urine for nicotine. If it's the latter, I am going to give him a switching, stopping about one stroke before CPS would need to be called. It's deliberate, it's certainly dangerous, it's disobedient, and lying about it was, best case, disrespectful. It's just too important an issue to let slide. Either way, he's going to be monitored a lot more closely, complete with "demeaning" whiz quizzes
It's too important a health issue to let slide for fear of hurting feelings. He's already betrayed my trust twice--there's no reason I should worry about him feeling I don't trust him. Given the scenario, I'd be a fool, and a poor parent, if I did.