Preheat your oven to 400°F and line a rimmed baking sheet with parchment paper for easy cleanup.
Slice the sweet potato into uniform 1/2-inch cubes and trim the tough ends from the asparagus spears.
In a small glass bowl, whisk together the olive oil, lemon juice, fresh zest, minced garlic, oregano, salt, and pepper.
Arrange the chicken breast and chopped vegetables on the prepared sheet, then drizzle the lemon-herb mixture over everything.
Toss the vegetables well to ensure they are evenly coated in the bright, citrusy marinade.
Roast for 20 to 25 minutes, adding the cherry tomatoes during the last 10 minutes of cooking until they are blistered and juicy.
Ensure the chicken reaches an internal temperature of 165°F before removing from the oven.
Let the chicken rest for 5 minutes to lock in the juices, then slice and serve with the roasted medley.