Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1/2-inch cubes, then slice the red bell pepper into thin strips.
Place the chicken breast, sweet potato cubes, broccoli florets, and bell pepper strips onto the prepared baking sheet.
In a small bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper until well combined.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing thoroughly with your hands or tongs to ensure everything is evenly coated.
Arrange the ingredients in a single layer on the tray, making sure the chicken breast is positioned in the center.
Roast in the oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing and serving alongside the caramelized vegetables.