Nasal tip pinching is often due to weakening of the nasal tip cartilage. This is usually best treated using cartilage grafting using grafts from the septum, ear or rib.
The goal is to restabilize and reorient the tip cartilages to create more natural tip contours. Another benefit of this approach is that often nasal airflow is also improved.
Web reference: http://www.drlamperti.com/facial-plastic-surgery/rhinoplasty