Prepare the chicken: Preheat the oven to 400°F.
Using a sharp knife, cut a deep pocket into the side of each chicken breast without cutting all the way through. Season both sides of the chicken with the salt, pepper, Italian seasoning, and garlic powder.
Make the filling: In a bowl, combine the ricotta, shredded mozzarella, Parmesan, basil, garlic, Italian seasoning, salt, and pepper until well mixed.
Fill each chicken breast with about ¼ of the mixture. Secure with toothpicks if needed.
Sear the chicken: Heat the olive oil in a large oven-safe skillet over medium-high heat. Cook the stuffed chicken for 3–4 minutes per side until nicely golden. It doesn't need to be fully cooked yet. Transfer the chicken to a plate.
Make the Capri topping: Reduce the heat to medium and melt the butter. Add the mushrooms and cook for 5–6 minutes until browned.
Stir in the garlic and cook for 30 seconds.
Add the cherry tomatoes and cook for 2–3 minutes, just until they begin to soften.
Pour in the chicken broth and simmer for 2 minutes, scraping up any browned bits from the pan.
Bake: Nestle the chicken back into the skillet. Top each chicken breast with a slice of fresh mozzarella.
Transfer the skillet to the oven and bake for 12–15 minutes, or until the chicken reaches 165°F internally.
Finish: Let the chicken rest for 5 minutes. Remove the toothpicks.
Garnish with fresh basil and serve immediately.