Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Chop the red bell pepper and zucchini into bite-sized pieces and break the broccoli into small, uniform florets.
Slice the chicken breast into even 1-inch strips or cubes to ensure they cook at the same rate as the vegetables.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken pieces and all the chopped vegetables to the bowl, tossing thoroughly until every piece is well-coated in the herb marinade.
Spread the mixture in a single layer across the prepared baking sheet, ensuring the pieces are not overcrowded so they roast rather than steam.
Roast in the center of the oven for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly caramelized edges.
Serve immediately while hot, optionally garnishing with extra fresh herbs or a squeeze of lemon if desired.