Preheat your oven to 400°F and line a large rimmed sheet pan with parchment paper for easy cleanup.
Dice the chicken breast and sweet potato into uniform 1-inch cubes to ensure they cook at the same rate.
Place the chicken cubes, sweet potato cubes, and broccoli florets onto the prepared sheet pan.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Drizzle the lemon-herb mixture over the chicken and vegetables, then toss with your hands or tongs until every piece is thoroughly coated.
Spread the ingredients out into a single layer, ensuring they aren't overcrowded so they roast rather than steam.
Roast for 22-25 minutes, or until the chicken is cooked through and the sweet potatoes are tender and lightly browned.
Garnish with freshly chopped parsley and an extra squeeze of lemon if desired before serving.