Prepare the chicken breasts by rinsing them under cold water and patting them dry. Slice a pocket into each chicken breast without cutting all the way through.

In a mixing bowl, combine cream cheese, spinach, mozzarella, Parmesan, garlic, Italian seasoning, salt, and pepper. Mix until well combined.

Stuff each chicken breast pocket with the mixture, securing openings with toothpicks if necessary.

Heat olive oil in an oven-safe skillet over medium-high heat. Sear the stuffed chicken breasts for 3-4 minutes on each side until golden brown. Pour chicken broth into the skillet and transfer to a preheated oven. Bake for 25-30 minutes until the internal temperature reaches 165°F. Let rest for 5 minutes before serving.