is my nose broken???????

Hi abby! if you were not feeling dizzy I would suggest you wait until it was less swollen which can take some days. It can be hard to see if a nose is broken when it is still swollen. You didn't mention about bleeding, sometimes (but also not always) you have bleeding when you have a broken nose. But because of course the head of your brother hits your head (including nose) we call this concussion injury, and concussion injury with dizziness = going to see the doctor. A physical exam is necessary. It can also happen that the doctor will ask you to come back after 1 week to check it again.

It is impossible to have a sprained nose, because sprain is a strecht of a ligament between two bones, and you don't have it in the nose.