Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and chop the zucchini, bell pepper, and asparagus into uniform chunks.
In a large mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Add the chicken and chopped vegetables to the bowl and toss thoroughly until every piece is evenly coated in the marinade.
Spread the chicken and vegetable mixture in a single layer on the prepared baking sheet, ensuring they are not overcrowded to allow for proper roasting.
Roast in the oven for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly caramelized at the edges.
Remove from the oven and serve immediately while hot, optionally finishing with a squeeze of fresh lemon.