Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Trim the woody ends off the asparagus spears and place them on the baking sheet, tossing with half of the olive oil and a pinch of salt and pepper.
Roast the asparagus in the oven for 12 to 15 minutes until they are tender and slightly charred at the tips.
While the asparagus roasts, pat the chicken breast dry with a paper towel and season both sides evenly with garlic powder, dried oregano, salt, and pepper.
Heat the remaining olive oil in a heavy-bottomed skillet or cast-iron pan over medium-high heat until shimmering.
Place the chicken in the hot skillet and sear for 6 to 7 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest on a cutting board for 3 to 5 minutes to lock in the juices before slicing.
Plate the sliced chicken alongside the roasted asparagus and finish the dish with a generous squeeze of fresh lemon juice over everything.