Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and place it on one side of the baking sheet.
Peel and cube the sweet potato into half-inch pieces, then place them on the baking sheet with the broccoli florets and sliced carrots.
In a small glass jar or bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper until well combined.
Drizzle the herb-lemon oil over the chicken and the vegetables, using your hands or a spatula to toss the vegetables until they are evenly coated.
Spread the ingredients into a single layer, ensuring the chicken has enough space for the skin to crisp up.
Roast in the center of the oven for 20 to 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 to keep the juices locked in.
Plate the sliced chicken alongside the roasted vegetable medley and serve immediately while hot.