Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato into half-inch cubes and trim the tough, woody ends off the asparagus spears.
Place the chicken breast, sweet potato cubes, and asparagus onto the prepared baking sheet in a single layer.
In a small glass jar or bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, sea salt, and black pepper.
Drizzle the herb and lemon mixture over the chicken and vegetables, using your hands or tongs to ensure everything is evenly coated.
Slide the pan into the oven and roast 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, then garnish with fresh parsley and serve warm.