I have a flat nose can i make it bigger without plastic surgery?

To some Extent: It can be made larger in certain areas with fillers - (but, fillers also have complications).

Sometimes: Volume can be added to the nose with fillers. Sometimes referred to as a "liquid nosejob" or nonsurgical rhinoplasty. Not everyone is a candidate. Choose your specialist carefully.

Liquid rhinoplasty: Some patients are candidates for a "liquid rhinoplasty" using a soft tissue filler (like Juvederm). However, you need to be seen in person before this can be recommended. I recommend that you see a board certified plastic surgeon.