Is it possible to fix my broken nose? I've never had any accident. Why does it look like this?

Based on your x-ray, you may have had a trauma at some point although you would likely remember being hit in the nose hard enough to break it.

If you don't feel like there is any cosmetic issues with your nose or you are not suffering from any significant breathing issues, you do not need to do anything. Whatever fracture you may have had is likely healed.