Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Scrub the sweet potato and pierce it several times with a fork, then place it on one side of the baking sheet.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast and the trimmed asparagus spears on the baking sheet next to the sweet potato.
Brush the lemon-herb marinade generously over both sides of the chicken breast and toss the asparagus to coat.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potato is tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure it remains juicy.