If your kitten is chewing on the bottle nipple instead of sucking, it could be due to several reasons. The nipple hole might be too small, making it difficult for the kitten to get milk, leading to frustration. Teething can also cause a kitten to chew. Alternatively, the kitten might simply be playful and exploring the nipple's texture. Try enlarging the nipple hole slightly, offering teething toys, or consulting with a veterinarian for advice on proper feeding techniques.