Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Cut the chicken breast into 1-inch bite-sized cubes and place them in a large mixing bowl.
Trim and halve the Brussels sprouts and chop the red bell pepper into 1-inch pieces, then add them to the bowl with the chicken.
In a small jar or bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Pour the dressing over the chicken and vegetables, tossing thoroughly to ensure every piece is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is space between the pieces for even browning.
Roast for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the vegetables are tender with charred edges.
Remove from the oven and immediately sprinkle with fresh lemon zest before serving.