Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Scrub the sweet potato thoroughly, pierce it several times with a fork, and place it on one side of the baking sheet.
In a small glass bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper until well combined.
Place the chicken breast on the baking sheet and brush it generously with half of the lemon-herb oil mixture.
Roast the chicken and the sweet potato in the oven for 15 minutes.
Remove the baking sheet from the oven, add the trimmed asparagus to the empty space, and drizzle the remaining lemon-herb mixture and fresh rosemary over the vegetables.
Return the sheet to the oven and roast for an additional 10 to 12 minutes, or until the chicken reaches an internal temperature of 165°F and the asparagus is tender.
Allow the chicken to rest for 5 minutes before slicing and serving alongside the roasted sweet potato and asparagus.