I think you are confusing emotion with intelligence. They are not dependent on each other completely.
First, why don't we define the terms a little better:
Intelligence is different from instinct or fixed action patterns that are hard wired into an animal's behavior through accumulated evolutionary influences. The animal is not analyzing what is best to do in a situation, it just does what the hard wiring tells it to even if the response isn't totally correct. For example...put a female duck in an enclosure she can't see out of. Put a duckling of a different species nearby so she can hear it. When the duckling starts calling for "mom", the female duck would try to get out of the box to reach the duckling. Instinct is telling her to respond to a baby's distress call. But, when she sees that the duckling is not hers, she may chase it away or try to kill it. Instinct is telling her to chase off an intruder or a competitor.
Emotions are communication behaviors...they express what an individual is thinking about and help them choose the appropriate response to survive a threat, avoid fights and injuries, to breed and raise young successfully, and carry on their genetics. But emotion also requires two individuals to work...one to express something and the other to interpret it and modify its own behavior. I'd say that solitary animals use emotional responses a little less than social (herding) animals do. They still need them, but they can be less complex. A solitary cham still needs to respond to competitors, threats, and potential mates.
Can an animal that is not known to be very intelligent be emotional? Sure!
My motmots are not known for their smarts but they are very emotional. They show devotion to each other, fear, anger, which are socially important. Many birds (with exceptions like corvids and parrots) are not known to be very intelligent; in other words, they rely a lot on instinctual memory rather than analytical thought. The theory for this is that birds gave up a lot of brain space to keep the size of their head smaller and more in balance with their bodies for flight and to allow space for their very large eyes and acute vision. Instinct takes up less brain space than analytical ability.
Can an animal that is intelligent not show emotion? It would be hard, but probably. Animals that are highly intelligent tend to be socially sophisticated and they would need more finely developed emotions that allow them to interact with others. But, I'd say an intelligent animal can learn to lay aside emotion in order to make a very rational decision.
So, after all this blather, chams can be relatively unintelligent but be very emotional. Their emotional range includes fear, aggression, and excitement but probably does not include "love". Breeding pairs don't nuture each other and they don't care for babies which would require some sort of altruistic emotional bond that can override their attempts to stay alive. I'd say your chams accept you as something not to be feared or as a source of good things, but I'd really doubt they love their keepers. You, as a highly intelligent social creature, are interpreting your cham's acceptance as affection because you really WANT it to like you. You want it to like you because that is an important feeling humans have...to be needed and accepted or loved.
My melleri Mufindi was a lovely friendly cham. She was her own self, an individual, with her own personality. Did she love me? Probably not. She felt peaceful and safe around me which made me enjoy her presence even more. This was my social creature's response to her behavior not necessarily her response to mine. Did I love her less because she isn't able to love me? No...I just thought about her differently.