Preheat oven to 400°F and line a large sheet pan with parchment paper.
Cut the chicken breast into 1-inch bite-sized pieces and slice the bell pepper and zucchini.
In a small bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken, broccoli, bell peppers, and zucchini on the prepared sheet pan.
Drizzle the lemon-herb marinade over the chicken and vegetables, tossing well to ensure everything is evenly coated.
Spread the mixture into a single layer to ensure even roasting and prevent steaming.
Bake for 18-22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.