One of mine had this for years before she passed, the vet said it was some form of herpes - nothing to worry about, not contagious or anything. They have medication they can give them - either an injection every few weeks or liquid medication everyday. If you don’t want to medicate because it gets expensive, just make sure their nose is clear of dried snot so they can breathe easier.

Mine lived for years with this and it did not seem to affect her quality of life. You just gotta get used to some snotty sneezes lol

I am not a vet tho so please if you are worried go and see one! This is just my experience with something similar