There is no proven way, beyond surgery, to make your nipples bigger. It's the same principle as making the penis bigger, or the clit, or even the breasts. A lot of products claim they will do it, but experienced medical professionals will very likely tell you that no product will ever make any part of your body "bigger."

One natural solution to enhancing the breasts and nipples without surgery is pregnancy, but that tends to lead to children. LOL