Nicotine drug test? How likely to be caught?

I am 15 and my parents might drug test me soon... I have been clean of everything except chewing tobacco for like 10 months. I am worrying about the nicotine, I have no clue how they are going to test me but I CANNOT get caught or else I am totally screwed. So how long does it take to get the nicotine out of my system? I do about 2 cans of copenhagen long cut original a week.