Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Prepare the vegetables by halving the baby potatoes and trimming the tough, woody ends off the asparagus spears.
In a small mixing bowl, whisk together the extra virgin olive oil, the juice and zest of the half lemon, minced garlic, oregano, garlic powder, sea salt, and black pepper.
Place the chicken breast and halved potatoes on the baking sheet; drizzle with two-thirds of the lemon-herb mixture, tossing the potatoes to ensure they are well-coated.
Roast in the center of the oven for 15 minutes.
Remove the pan briefly to add the asparagus spears to the remaining open space, drizzling them with the rest of the herb oil.
Return the pan to the oven and roast for an additional 10 to 12 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender and golden.
Allow the chicken to rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetables.