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 even 1-inch bite-sized pieces to ensure they cook quickly and remain juicy.
Chop the broccoli into small florets and slice the red bell pepper into thin strips.
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 and vegetables onto the prepared sheet pan and pour the lemon-herb marinade over them.
Toss everything thoroughly with your hands or tongs until every piece is evenly coated, then spread into a single layer.
Roast in the oven for 18-22 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender-crisp.
Serve immediately, perhaps with an extra squeeze of fresh lemon for a bright finish.