LLLOOOLLL
What a hilarious question.
The way you phrase your question, the answer would be:
'If you got bit by anything with HIV blood in its teeth, you'd get it, but only if it's fresh.'
HIV won't survive in the mouth of a chameleon too long, especially if the chameleon opens its mouth while basking. It's a primate disease. We got it from monkeys in 1940, it spread to America in 1980, it wasn't even able to be tested for until 1985. It's not a very infectious disease at all, actually. It's just the rough 'intercourse' (read: rape), they have in Africa creates lesions which causes the transmission of blood, causing AIDS. If a man had normal intercourse with a woman who had AIDS, his likelihood of contracting AIDS is roughly 1% (no blood involved).
Rape and needle sharing is the main cause of the transmission of AIDS.
I think your concern would be if some chameleon farmer with AIDS in Tanzania got bit by your chameleon while being stuffed into a package to be shipped, would the virus survive long enough to be transmitted to you?
Open air the HIV/AIDS Virus last about 30 seconds to 1 minute, in a wet media like blood or other liquid that is exposed to air it will live for about 2-5 minutes, in perfect lab conditions the virus will live for about 20-40 minutes.
Hepatitis B can live up to 2 weeks outside the body, and other Hepatitis viruses can live some time as well (just google it)
It's very, very unlikely of getting anything from a chameleon...