He's pulling your leg.
But seriously, chameleons might be venomous (I suppose).
Many snakes and lizards we think of as non-venomous are in fact venomous.
Bearded dragons for example have venom similar to rattlesnake venom, but delivered in such small amounts it does not have effect on us.
This was found true for most lizards several years ago (most snakes too), so although I do not know if they are venomous or not, it would not surprise me to learn that chameleons were also venomous.
(Poisonous=if you bite it, you are harmed, venomous=if it bites you, you are harmed. So poisonous vs venomous all depends on who is biting who

).
And no, I am not joking.
A link for starters:
http://www.newscientist.com/article/dn8331-lizards-poisonous-secret-is-revealed-.html
Another good link:
http://www.leidenuniv.nl/en/researcharchive/index.php3-c=134.htm