Preheat oven to 400°F and line a large baking sheet with parchment paper.
Cut the chicken breast into 1-inch cubes and chop the broccoli, carrots, and bell pepper into bite-sized pieces.
In a large mixing bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, sea salt, and black pepper.
Add the chicken and vegetables to the bowl, tossing thoroughly until every piece is evenly coated in the aromatic herb mixture.
Spread the mixture in a single layer on the prepared baking sheet, ensuring space between pieces for even roasting.
Roast for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly caramelized edges.
Garnish with fresh parsley and serve immediately while hot.