Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel the sweet potato and cut it into 1-inch cubes, then trim the tough, woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus onto the prepared sheet pan in a single layer.
Drizzle the olive oil over the chicken and vegetables, ensuring everything is lightly coated.
In a small bowl, mix the rosemary, thyme, garlic powder, sea salt, and black pepper, then sprinkle the spice blend evenly over the entire pan.
Toss the vegetables to distribute the seasoning and flip the chicken once to coat both sides.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender and slightly browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.