Preheat the oven to 375°F (190°C).

In a mixing bowl, combine the Italian breadcrumbs, grated Parmesan cheese, shredded mozzarella cheese, chopped fresh basil, chopped fresh parsley, minced garlic, salt, and black pepper.

Use a sharp knife to butterfly each chicken breast, cutting horizontally through the thickest part of the breast, without cutting all the way through.

Divide the breadcrumb mixture into 4 equal portions. Place a portion of the breadcrumb mixture onto each chicken breast, then fold the chicken breast over to enclose the filling.

Secure the chicken breasts with toothpicks to hold the filling in place.

Heat olive oil in a large oven-safe skillet over medium-high heat. Add the stuffed chicken breasts and cook for about 3-4 minutes on each side, until golden brown.

Transfer the skillet to the preheated oven and bake for about 15-20 minutes, or until the chicken is cooked through and no longer pink in the center.

Remove the toothpicks and serve the Italian stuffed chicken breasts warm.