Welcome to the forums!
Dubia are a great choice of feeder!
but for chameleons, variety is usually the best thing possible.
Some good feeders:
Crickets-staple
Dubia & most any other roach- staple
Silk worms- Staple/treat
Horn worms- treat
Super worms - treat
of course there are many more! this is just a simple list to give you an idea. Those foods listed as treats are also nutritionally well balanced, essentially everything on this short list is good for your chameleons

.
But, just because your using good feeders, does not mean you can skimp on the gutload. a variety of feeders being fed a variety of gutloads will ensure healthy and usually problem free chameleons. Not excluding supplementation of course.
Regarding dubia strictly, they are wonderful - I have my own colony going (shout out to ChameOh

). Do you want to start a colony right away? if thats so then you should start with quite a few female & male pairs (aka dozens) with a a few hundred juvis & nymphs to feed off of while you wait.
Hope this helps! and im sure people with more experience than i with the roaches will chime in as well
S.F