Marinate the Chicken: In a large resealable plastic bag or shallow dish, combine the chicken breasts with the Italian dressing. Seal the bag or cover the dish and refrigerate for at least 30 minutes, or up to 8 hours for better flavor.

Preheat Oven: Preheat your oven to 400°F (200°C). Lightly grease a large baking sheet or line it with parchment paper.

Prepare the Vegetables: In a large bowl, toss the baby potatoes, baby carrots, cherry tomatoes, zucchini slices, red bell pepper, and yellow bell pepper with the Italian seasoning, garlic powder, onion powder, salt, and black pepper until evenly coated.

Arrange on Baking Sheet: Spread the marinated chicken breasts in a single layer on the prepared baking sheet. Arrange the seasoned vegetables around the chicken.

Bake: Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through (internal temperature reaches 165°F or 74°C) and the vegetables are tender and slightly caramelized.

Garnish and Serve: Garnish with freshly chopped parsley before serving.