It sounds like an upper respiratory problem to me. I would get her to a herp vet straight away before it gets worse. The vet will be able to provide you with an antibiotic treatment and a vitamin A booster.
Don't wait too long. Like with everything else, torts take a long time to show illness. If she is bubbling at the nose the illness is likely already advanced. Waiting too long can be a fatal move.
If you have any other reptiles you need to quarantine her from them. The infection (if that is what she has) can be contagious and you don't want to have to provide antibiotic to any more pets!

Also practice good quarantine procedures and always wash your hands after you touch her or clean her area.
Until you can see a vet you should try to keep her warm. Raise the temps a few degrees under her basking light in her enclosure. Heat helps ward off the infection.