Depends. Injectable compounds can give you small changes in the shape of the nasal dorsum (profile of the nose). However, this is only suitable for specific noses, and not applicable to everyone. If you desire changes in your nasal tip, nasal base, or if there is twisting of th bony nose, surgery is generally necessary. An experienced rhinoplasty surgeon can tell you your options, surgical or otherwise.
Yes, but..... Fillers such as juvederm can be used to slightly improve a small bump on the dorsum of the nose. It can also be used to augment the tip or soften superficial defects. Subtle improvements, but noticeable! alas, they are temporary and last for about a year. : (.
No. Unless caused by trauma, the shape of the nose cannot be changed without surgical intervention.