Pat the chicken breasts dry using paper towels before seasoning. Dry chicken browns much better on the grill. Coat both sides with olive oil to help the spices stick evenly.
Mix the garlic powder, onion powder, paprika, oregano, thyme, salt, and black pepper in a small bowl. Rub the seasoning generously over both sides of the chicken. Toss the vegetables with a little olive oil and any remaining seasoning.
Heat your grill or grill pan over medium-high heat. A properly heated grill helps create beautiful grill marks while preventing the chicken from sticking.
Place the chicken on the hot grill and cook for about 6–8 minutes on the first side. Flip it carefully and cook another 6–8 minutes until the internal temperature reaches 165°F (74°C).
Arrange the vegetables on the grill in a single layer. Turn them every few minutes so they cook evenly without burning. They should become slightly charred while remaining crisp-tender.
Transfer the grilled chicken to a plate and let it rest for about five minutes. Resting allows the juices to stay inside the meat instead of running out when sliced.
Slice the rested chicken against the grain into even strips. This keeps every bite tender and easier to eat.
Arrange the grilled vegetables on one side of the serving platter. Place the sliced chicken beside them for a colorful presentation.
Drizzle fresh lemon juice over everything before serving. Sprinkle chopped parsley on top for extra freshness and enjoy while warm.