In a small bowl, make the marinade. Whisk olive oil, garlic, lemon juice, and seasonings together. Thread chicken, mushrooms, bell peppers, onion, and zucchini onto the skewers and place in a shallow dish. Brush skewers with marinade and place them in the refrigerator to marinate for 15-30 minutes. Grill over medium-high heat, turning periodically, until chicken is cooked through and its internal temperature registers at 165 degrees F (10-15 minutes). Remove from grill and serve.