Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Wash and halve the baby potatoes, and trim the woody ends off the asparagus spears.
In a mixing bowl, toss the halved potatoes with half of the olive oil, sea salt, and black pepper.
Spread the potatoes onto the prepared baking sheet and roast for 15 minutes to give them a head start.
While potatoes roast, pat the chicken breast dry and rub with the remaining olive oil, lemon juice, oregano, garlic powder, and chopped fresh rosemary.
Remove the baking sheet from the oven, move the potatoes to one side, and add the chicken breast, asparagus, and cherry tomatoes.
Return the sheet to the oven and roast for an additional 18-22 minutes, or until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the crispy potatoes and roasted vegetables.