You can OD. However, it's sort of funny how no one's warned that they might OD while chain smoking. I have friends who use more than the recommended doses of NRT. One friend wears three patches, still one year later. Obviously, he is now addicted to the patches. That may be one problem of overusing NRT.
I used NRT to quit and I don't at all regret it. However, NRT can become addictive and, therefore, those of us who use it should have an exit plan.