Preheat your grill to medium-high heat.
In a large bowl, combine olive oil, Parmesan cheese, minced garlic, Italian seasoning, salt, and black pepper. Mix well to create a marinade.
Add the chicken breasts to the marinade, ensuring they are well coated. Cover the bowl and let the chicken marinate for at least 30 minutes, or up to 2 hours in the refrigerator for more flavor.
Once marinated, remove the chicken from the bowl and discard any remaining marinade.
Place the chicken on the preheated grill. Cook for 6-7 minutes on each side, or until the internal temperature reaches 165°F and the chicken is golden brown.
Remove the chicken from the grill and let it rest for 5 minutes before slicing.
Garnish with chopped parsley before serving.