Why does the nostril base become wider from jaw surgery? Can I have this procedure specifically to widen my nostrils?

During jaw surgeries where the upper jaw is moved forward, the skin over the bony nose widens because it is essentially be stretched forward to accommodate the new jaw position. This procedure is not done specifically to widen the nose unless you have jaw issues. The attachment of the nasal base to the bones can be released through an incision in your mouth to achieve some widening. This alar release procedure or a revision rhinoplasty/alarplasty may address your concerns better than a jaw surgery. A clinical exam would be needed to give you the best treatment plan for your specific situation.