Dude, do you mean there is some scratches on your lenses? You can remove them in some ways. But you may remove the coating on the surface of the lenses. The lenses without coating can't block harmful UV rays for your eyes. So I suggest you not to remove it if there is only a tiny nick on the lens.
I suggest you to turn to an optician immediately. Your sunglasses are very expensive. It could be a great loss if you remove the tiny nick in an inappropriate way. I bought a pair of new sunglasses last month. I seldom use them because the summer is gone. But I decided to buy them because I come across a discount. I think they worth that money. They cost me more than $200. I often put them back to the case when I don't need to wear them. In this way, I can better protect my sunglasses and avoid some scratches.
Sweetie, where is nick? If it is on the frame, you can fill the nick with acrylic powder and touch up the nick with some nail polish. I have tried that. It works. But you must be careful when doing this because you may ruin your sunglasses if you drop some nail polish on your lenses. Though there is some way to remove them, you may remove the coating as well. That can be a great lose for you to suffer. So be careful! If you can't manage this, you can go to a nail salon and ask other people to do it for you.