I shred everything (like coleslaw consistency- shred and chopped) and mix it all together so a variety gets picked up on the tongue.
Pretty much anything you can eat is fine, just remember to easy on spinach, broccoli, cabbage and lettuce. Some is good, but all the time is probably not so good (although it probably matters less with chameleons because the insects form the bulk of the diet and minimize the percentage of these veggies that are taken in anyway- but the more percentage the veggies, the more it matters to use the above families of veggies in limited quantity.
If you read up on iguana recipes, usually they explain the whys a little better (calcium binders, goiterigens (spelling?), low nutritional value for examples on my short list above. But that doesn't mean occasional use is not beneficial- it is- variety is best. Some hobbyiests get the wrong idea from a little information about nutrition that these should be avoided entirely. Just not true.
As far as organic or not- depends on your feelings on the topic. People have had success either way. Personally, I have tried to go more organic myself the past few years, and try feed the animals accordingly as well. Last summer I grew all the greens I needed for my lizards in my own garden from heirloom seeds. But this winter I have been buying a lot of their greens on the cheap at the local supermarket. So I'm not perfect.