Unfortunately MOST school administrations are really in the dark when it comes to handling bullying. If I were you I would pay a visit to the school's discipline administrators, and cover several things here -1) The fact that when something is done to your daughter on the bus and there is video documenting that -you DEMAND a punishment be handed out. Even if it's just detention -it starts a chain of documentation in case something escalates between her and that student.
I wouldn't demand payment for the shirt from that incident, but if there is video of it, I WOULD demand punishment for the student who did it.
2) In NO way should anyone be allowed to call your daughter a Nazi! I would find that term horribly offensive as well. The school should punish the person or people calling your daughter that in the same way they would any other student using a racial slur or derogatory name. You should demand the student's parents be contacted, and if you know who they are -call them yourself and ask if they know their child is calling another kid a Nazi.
Often schools have to be made to realize that it's going to get very uncomfortable for them if they don't take action. That can include a visit to your local news channel. Bullying is a HOT topic right now that all the news stations want to report on, so I would bring that up to the school administration as well. You might be surprised at how fast that commands some action.