Place broccoli, cauliflower, red bell pepper strips, onion, and water in a microwavable safe bowl. Cover the bowl, and microwave for 5 minutes. Drain water from vegetables.
In a very small microwaveable bowl, place butter. Cook in microwave for 15-20 seconds, or until the butter is melted. Toss 1 tablespoon of the butter with the vegetables.
Brush remaining 1/2 tablespoon melted butter on both sides of the chicken pieces.
Spray 2 baking pans with cooking spray.
In a medium bowl, combine the Parmesan cheese, Italian salad dressing mix, and garlic powder. Toss 1/3 cup of the Parmesan mixture in with the bowl of vegetables.
Use the remaining Parmesan mixture to coat both sides of the chicken. Place chicken in one baking pan, and the vegetables in the other baking pan. Spray the top of the chicken with cooking spray.
Bake both the vegetables and the chicken for 22-25 minutes, or until the chicken is fully cooked.
Serve 1 chicken breast with approximately 1/2 cup floret mixture.