Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash and dice the red potatoes into small 1/2-inch cubes to ensure they cook at the same rate as the chicken.
Trim the woody ends off the asparagus spears and set them aside.
In a large mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken breast, diced potatoes, and asparagus to the bowl, tossing thoroughly until every piece is evenly coated in the herb oil.
Spread the chicken and potatoes onto the prepared baking sheet in a single layer, leaving space for the asparagus to be added later.
Roast for 15 minutes, then add the asparagus to the sheet and continue roasting for another 10-12 minutes until the chicken reaches an internal temperature of 165°F.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure the juices redistribute for a tender finish.