Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Cut the chicken breast, sweet potato, and bell pepper into uniform 1-inch cubes.
In a large mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken, sweet potato, bell pepper, and broccoli florets to the bowl and toss thoroughly until every piece is coated in the herb oil.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces are not overcrowded so they roast rather than steam.
Place the pan in the oven and roast for 20 to 25 minutes, or until the chicken is cooked through and the sweet potatoes are tender and golden brown.
Remove from the oven and let rest for 2 minutes before serving.