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 uniform 1-inch cubes, then trim the woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus on the prepared sheet pan in a single layer.
Drizzle the olive oil over the chicken and vegetables, ensuring everything is lightly coated.
Evenly sprinkle the sea salt, black pepper, dried rosemary, and garlic powder over all the ingredients on the pan.
Toss the vegetables with your hands or tongs to distribute the seasoning, and flip the chicken to coat both sides.
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 potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy, then serve immediately.