Start by cutting the chicken breasts into 1-inch cubes and soak wooden skewers in water for 30 minutes if using.

In a mixing bowl, combine Parmesan cheese, white vinegar, olive oil, lemon juice, garlic powder, oregano, onion powder, and red pepper flakes. Stir to create a marinade.

Toss the chicken cubes in the marinade, ensuring they are well-coated. Cover and refrigerate for at least 30 minutes.

Thread the marinated chicken onto skewers, alternating with vegetables if desired.

Preheat grill to medium heat, around 350°F, and lightly oil the grates.

Grill the kebabs for about 5 minutes on each side, aiming for an internal temperature of 165°F.

Remove from grill and let rest for a minute before serving.