Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and dice the sweet potato into 1/2-inch cubes, and trim the tough, woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus on the prepared sheet pan in a single layer.
In a small glass jar or bowl, whisk together the olive oil, lemon juice, garlic powder, dried oregano, sea salt, and black pepper.
Drizzle the lemon-herb mixture over the chicken and vegetables, using your hands or a brush to ensure everything is evenly coated.
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 to lock in the juices before slicing and serving.