Housing two chameleons together does not always result in a sick/stressed animal. Under the right conditions and with a great amount of monitoring it is possible to house two or more chameleons together. With certain chameleons it often makes them less aggressive, stressed, and less likely to lay eggs as often and in smaller numbers.
That being said, if you have to ask, don't do it. It obviously shows you do not have the right amount of experience or knowledge to take on such a task.