They like to be high and covered so more plants and vines up high would be good.
Give him time i am going through the same thing now. Same enclosure added him a week ago and he is just now getting his color back and starting to calm down. some fake plants and vines at the top (enough for him to hide) and some time and he should do just fine.
it's my first cham "not first reptile" so im kinda new and i was about to post a thread about why he was showing ugly colors and I have put a fake vine up where he likes to bask will post new pics when i get a chance thanks for the great review