Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into bite-sized 1-inch pieces and slice the bell pepper and red onion into uniform strips.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken pieces, broccoli florets, bell peppers, and red onion onto the prepared sheet pan.
Pour the lemon-herb marinade over the ingredients and toss thoroughly with your hands or tongs to ensure every piece is well-coated.
Spread the mixture out into a single, even layer across the pan to allow for proper roasting rather than steaming.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is golden and reaches an internal temperature of 165°F.
Remove from the oven and let rest for 5 minutes before dividing into meal prep containers for the week.