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 chop the broccoli and red bell pepper into uniform sizes to ensure even cooking.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken pieces and chopped vegetables onto the prepared sheet pan.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing thoroughly with your hands or tongs to coat every piece.
Spread the mixture out into a single layer, ensuring there is space between the items to allow for proper roasting rather than steaming.
Bake for 18 to 22 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly browned.