Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and cut it into 1-inch cubes, and trim the woody ends off the asparagus spears.
Pat the chicken breast completely dry with paper towels to ensure the skin gets extra crispy during roasting.
In a small bowl, combine the dried oregano, garlic powder, minced fresh rosemary, sea salt, black pepper, and the zest of the lemon half.
Toss the sweet potato cubes on the baking sheet with half of the olive oil and a pinch of the herb seasoning.
Rub the chicken breast with the remaining olive oil and the rest of the herb mixture, then place it on the baking sheet next to the potatoes.
Roast for 15 minutes, then add the asparagus to the tray, tossing them in the pan juices, and roast for another 10 to 12 minutes until the chicken reaches 165°F.
Squeeze the fresh lemon juice over the chicken and vegetables just before serving for a bright, clean finish.