Preheat your oven to 425°F (220°C) and line a large baking sheet with parchment paper.
Dice the sweet potato into small 1/2-inch cubes and trim the woody ends off the asparagus spears.
In a small bowl, whisk together half of the olive oil, the lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken breast on one side of the baking sheet and brush it thoroughly with the lemon-herb marinade.
Toss the sweet potato cubes with the remaining half of the olive oil and a pinch of salt, then spread them in a single layer on the other side of the baking sheet.
Roast for 10 minutes, then remove the sheet from the oven and add the asparagus and cherry tomatoes to the tray.
Return the tray to the oven and continue roasting for 12-15 minutes until the chicken reaches an internal temperature of 165°F and the sweet potatoes are tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy and flavorful.