In a small bowl, whisk together 1 tablespoon of olive oil, the 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 the marinade over it, ensuring both sides are thoroughly coated, then let it sit for 10 minutes.
While the chicken marinates, slice the zucchini into half-inch rounds, cut the bell pepper into wide strips, and trim the woody ends off the asparagus.
Toss the prepared vegetables in a bowl with the remaining 0.5 tablespoon of olive oil until lightly coated.
Preheat your grill to medium-high heat and lightly oil the grates to prevent sticking.
Place the chicken on the grill and cook for 6 to 7 minutes per side, or until the internal temperature reaches 165 degrees Fahrenheit.
Add the vegetables to the grill during the last 8 minutes of chicken cooking time, turning them occasionally until they are tender and have distinct char marks.
Remove everything from the grill and let the chicken rest for 5 minutes before slicing it to serve alongside the grilled vegetables.