Are they viable anymore in 8th? Shooting Modifiers... -1 Multiple shots -1 Move/March -1 and typically long range (12"range on the blowpipes) so 6's to shoot.... ouch! 5's if they dont move. But by then the guys im usually shooting charges, decimating the unit with no armour or ward saves to speak of....*cry* The only thing they could do well against are war machines. Deploy in their deployment zone, preferably behind their other units.
Chameleons are essential in 8th! Normally, they hit on 3s. You start 12 inches from your target (even at 24 inches). If you start at 12 inches, march 12 inches (you are within 6 inches of the target). You then get -1 for move, -1 for double tap. So, that puts you hitting on 5s and poison on 6s. If you are 24 inches, that puts an additional -1 for being greater than 6 inches, you are still poisoning on 6s. These guys are amazingly effective. I played a game on Saturday against HE. I took 2 units of 5 chameleons. They earned their points, and then some. If they cause my opponent to alter one unit to face them, it is worth it. I moved one unit all around that unit and took out a balista with them. Well worth their points.
scout the chameleons and don't let him look at them. if he tryes to position more units to be able to charge them just dance around him with a 12" march since you can't get march blocked right now (well you get a Ld test, but with their Ld cold blooded i think you pass it more often than not). also, use them to kill war machines or elite inantry. anything with guard in its name has a 5+ armor save also a lot of the elite infantry from other races. TG have 4+, stormvermin have 5+, hammerers have 5+ and the list goes on. don't shoot cavlary or hordes with skinks, not usefull.