Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and place them in a large mixing bowl.
Chop the red bell pepper and zucchini into similar bite-sized pieces and add them to the bowl along with the broccoli florets.
In a small jar or bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Pour the lemon-herb marinade over the chicken and vegetables, tossing thoroughly to ensure every piece is evenly coated.
Spread the mixture in a single, even layer onto the prepared sheet pan, ensuring nothing is overcrowded to allow for proper roasting.
Roast in the center of the oven for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly browned edges.