Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and place them in a large mixing bowl.
Prepare the vegetables by chopping the broccoli into small florets, slicing the bell pepper into thin strips, and dicing the red onion.
Add the vegetables to the bowl with the chicken, then drizzle with the extra virgin olive oil.
Sprinkle the dried oregano, garlic powder, sea salt, and black pepper over the mixture and toss thoroughly to ensure everything is evenly coated.
Spread the chicken and vegetables in a single layer on the prepared sheet pan, ensuring they aren't overcrowded so they roast rather than steam.
Place the pan in the oven and roast for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized.
Remove the pan from the oven and immediately drizzle with fresh lemon juice and sprinkle with lemon zest to brighten the flavors before serving.