hi Xim, (and ANYONE who ever reads this)
diagnostics across the Internet are terrible to do, often wrong, and sometimes dangerous. with that said, imo she (i don't think i know her name?) is in a pretty serious situation right now. the list of things i know of and/or have seen that cause a uniltareal nosebleed does not have too many nice things on it except for a dry little nosebleeds from low humidity, but i don't think that's her issue right now.
the diseases that will primarily cause this in chams are partial or full obstruction of the nasal canal/sinuses, or a systemic (bodywide) disease which is causing inappropriate bleeding as one of the secondary consequences (DIC/various anemias).
obstructions are typically from foreign bodies, but as a chameleon's nasal passage is so minuscule, it would be difficult for anything of any consequence to get up there. so we have to consider something that started growing on the inside rather than have come in from the outside. typically we see growths from neoplasia (cancer), a fungal disease, a parasite, or some irritating situation that causes a granuloma to form and grow.
systemic diseases that get bad enough to affect the body's ability to clot properly and cause spontaneous bleeds (in addition to blood clots, internally), tend to be the flip side of the coin. and literally almost any disease has the capability for this to happen, but usually it tends to be something drastically serious.
so again, imo, she's got something not very good going on. i don't believe stress is her primary issue, but i will definitely promise you that stress still is a factor here. i'm going to be honest and let you know from what you described that there are enough defecits in her heating, lighting, and humidity that they are currently not a healthy environement for her, and may have even predisposed this situation to happen. no matter what happens, you can still take care of her or maybe another cham even better.
it's your call what you want to do, but doing bloodwork and/or an xray right now and getting her on medication may save her life. it may not. maybe you want to just know what happened to see if it was unavoidable, or if if maybe it came from something you did so you know not to do again. i do think that if you don't try to intervene with veterinary care, either she may go very quickly on us, or she will continue on for some time but eventually succumb to the situation.
i hope this reads ok; it's a bit weird to try and speak exam room on a keyboard. but i know that i and most people who will read this do because we care a lot about chameleons, and that includes yours. i just hope this helps you and/and some other people, somewhere.
dr.o-
this is taheris nose after it stopped bleeding. She is very upset. 
I think she likes being out on the vine more then in her house. I think I want to try free ranging her. Just have to figure out heat and uv. Perhaps a murcury vapor bulb over the plant she likes? Do y'all think this would help her stress.
. only 50$ and 30$ for antibiotics. And they said she looks great other then the swelling in her sinus. Most likely cancer. As dr o said. But running a course if antibiotics orally to see if it can bring it down. If not. Then no treatment options are promising or realistic. 
