Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut it into 1-inch bite-sized pieces for even cooking.
Chop the broccoli, red bell pepper, and zucchini into uniform pieces and place them on the baking sheet alongside the chicken.
In a small bowl, whisk together the olive oil, minced garlic, lemon juice, dried oregano, sea salt, and black pepper.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing thoroughly to ensure every piece is well-coated.
Spread the mixture in a single layer and roast for 18-20 minutes, or until the chicken is cooked through and the vegetables are tender-crisp.
Remove from the oven and finish with an extra squeeze of fresh lemon if desired before serving.