Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut it into 1-inch bite-sized cubes.
Slice the red bell pepper into thin strips and chop the broccoli into small, uniform florets.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Add the chicken cubes, broccoli, and bell peppers to the bowl, tossing thoroughly until every piece is well-coated in the lemon-herb marinade.
Spread the mixture in a single layer across the prepared baking sheet, ensuring the ingredients are not overcrowded to allow for proper roasting.
Bake for 18 to 22 minutes, or until the chicken is cooked through and the vegetables have developed slightly charred, golden edges.
Remove from the oven and serve immediately, optionally garnishing with extra fresh herbs or a final squeeze of lemon.