I fed my chams mealworms from an early age with no ill effect, but if I knew what I know now, I'd probably avoid doing it again.
Mealworms are tougher to digest (due to the chitin content) and are also not very nutritious feeders (high fat content for relatively low protein, and the gutloading potential is limited).
They can be offered as a supplemental treat provided the cham is healthy and will be able to digest it easily, but if you do decide to use them try to pick out the recently molted ones - supposedly the chitin is easier to digest before it has hardened.
Feed them sparingly - a young cham will try to each as much as it can, and I suspect that if mealworms are ever to cause an intestinal blockage (impaction), it would be because of having overfed on them.
If you have the option, rather use silkworms or appropriately sized superworms.