Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Wash the sweet potato and cut it into 1/2-inch cubes; trim the woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus on the prepared baking sheet in a single layer.
In a small bowl, whisk together the olive oil, lemon juice, dried rosemary, garlic powder, sea salt, and black pepper.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing the vegetables gently to ensure they are evenly coated.
Roast in 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.
Let the chicken rest for 5 minutes before slicing and serving alongside the roasted vegetables.