Preheat oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Cut the chicken breast into 1-inch cubes and dice the sweet potato into half-inch pieces to ensure even cooking.
Place the chicken, sweet potato, broccoli florets, and sliced bell peppers onto the sheet pan.
In a small jar, whisk together the olive oil, lemon juice, oregano, garlic powder, sea salt, and black pepper.
Pour the dressing over the ingredients and toss thoroughly with your hands or tongs to coat every piece.
Spread everything out into a single layer, making sure the pan isn't overcrowded so the veggies roast rather than steam.
Roast for 20 to 25 minutes until the chicken reaches an internal temperature of 165°F and the potatoes are tender.
Remove from the oven and let rest for 5 minutes before serving or portioning into meal prep containers.