I'm afraid I disagree with the above reply. "Nothing will come of you now" means that you will not become anything much, or anything good. If someone fails all their exams at school, for example, someone might say "Nothing will come of him/her now" meaning that they won't get a good job, or they won't become anything or anyone significant.
I think "your lights are extinguished" is a somewhat colloquial addition to the phrase, as if to say "any light of hope that you would become someone good or interesting, has now been extinguished/put out".