Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and dice it into 1/2-inch cubes; trim the woody ends off the asparagus spears.
Place the chicken breast, diced sweet potatoes, and asparagus on the prepared sheet pan.
In a small bowl, whisk together the olive oil, minced garlic, lemon juice, dried oregano, sea salt, and black pepper.
Pour the lemon-herb mixture over the chicken and vegetables, tossing everything thoroughly to ensure an even coating.
Spread the ingredients out into a single layer, ensuring the chicken has enough space to roast evenly.
Bake for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.