In a small bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken breast in a shallow dish and pour half of the marinade over it, ensuring it is well coated.
Slice the zucchini into rounds, the bell pepper into wide strips, and trim the woody ends off the asparagus spears.
Toss the prepared vegetables with the remaining marinade in a large bowl until evenly coated.
Preheat your grill or grill pan over medium-high heat until hot.
Grill the chicken for 6 to 7 minutes per side or until the internal temperature reaches 165 degrees Fahrenheit.
While the chicken cooks, place the vegetables on the grill and cook for 4 to 5 minutes per side until they have beautiful char marks and are tender-crisp.
Let the chicken rest for 5 minutes before slicing and serving alongside the grilled vegetable medley.