Neonate
Spiders are usually a readily eaten food by chameleons, just as other insects. As noted, the problem will likely lie in avoiding those spiders that may be poisonous or otherwise problematic. In the wild, I assume that chameleons rarely get themselves into trouble by eating the wrong bug, that being a bug prone to harm its consumer. Natural selection would seem to eliminate that trait.
With our greenhouse, spiders abound. Probably about 6 different species, to include black widows. I often observe chameleons eating the non-poisonous species, to include the large wolf spiders (see below). If you were knowledgable enough to only offer relatively non-toxic spiders, I see no problem.