Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Pat the chicken breast completely dry with a paper towel and place it on one side of the prepared baking sheet.
Trim the tough, woody ends off the asparagus spears and arrange them in a single layer on the other side of the sheet.
In a small bowl, whisk together the olive oil, minced garlic, dried oregano, sea salt, and black pepper until well combined.
Drizzle the herb oil mixture over both the chicken and the asparagus, using your hands or a brush to ensure even coating.
Thinly slice the lemon half and place the rounds directly on top of the chicken and asparagus for infused flavor.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep the meat succulent and juicy.