Do big mustaches and beards help disguise a large nose from a profile view?

Growing a beard or goatee will in fact reduce the appearance of a small or weak chin.  When the chin is small relative to the nose, the nose will look even larger in relation.  By increasing the size of the chin - or at least making it appear larger - by either augmenting it with chin augmentation or growing facial hair, the nose will appear smaller.  

A beard and a mustache can help disguise a weak chin profile, but not disguise a large nose. Computer imaging may also be of some help to give you an idea what you may  look like after the rhinoplasty procedure. Rhinoplasty is a very difficult endeavor, so choose your surgeon wisely based on extensive experience. For many examples of what can be accomplished with a rhinoplasty, please see  the link below