Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Scrub the sweet potato and cut it into 1/2-inch cubes, then toss them on the sheet with half the olive oil and a pinch of salt and pepper.
Roast the potatoes for 15 minutes until they just start to become tender.
Season the chicken breast evenly with the garlic powder, dried oregano, and the remaining salt and pepper.
Push the potatoes to one side of the pan, place the chicken in the center, and add the trimmed asparagus to the other side.
Mince the garlic clove and whisk it with the remaining olive oil and the juice from half a lemon, then drizzle this mixture over the chicken and asparagus.
Return the pan to the oven and roast for another 15 to 20 minutes, or until the chicken's internal temperature reaches 165°F.
Remove from the oven and let the chicken rest for 5 minutes before serving to ensure it stays incredibly juicy.