A large chin can give the appearance that the nose is too small just as a small chin can make the nose look more prominent.
Frequently, surgery on either the nose or the chin may help to harmonise the facial balance and provide a natural aesthetic appearance. Occasionally, both aspects of the face may need to be addressed.
There are many small muscles of the face that work synergistically to produce facial expression. These are surrounded by fat pads. Together, they act to produce appearances that unique to the individual. Often, the pronounced nose or chin may be further amplified by movements such as smiling. In the chin region (otherwise known as the mental region!), prominence may be due to a combination of the mental fat pad as well as mandibular (jawbone) prominence.
Important to discuss your aims carefully. Surgery should achieve an aesthetically balanced chin, mid-face and upper face.