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 bite-sized cubes and chop the broccoli, bell peppers, and zucchini into uniform pieces.
In a small bowl, whisk together the olive oil, lemon juice, garlic powder, oregano, sea salt, and black pepper.
Place the chicken and vegetables on the prepared sheet pan and drizzle the lemon-herb mixture over everything.
Toss well with your hands or tongs to ensure every piece is evenly coated, then spread them out in a single layer.
Roast for 18-22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.
Remove from the oven and serve immediately, perhaps with an extra squeeze of fresh lemon if desired.