1. Prepare the Filling: Begin by heating 1 tablespoon of olive oil in a skillet over medium heat. Add the chopped onion and sauté until softened, about 3-4 minutes. Stir in the minced garlic, Italian seasoning, salt, and pepper, and cook for an additional minute to release their aromas. Next, add the sliced mushrooms and continue cooking until they’ve softened and any excess liquid has mostly evaporated, approximately 5-7 minutes. Transfer the mushroom mixture to a bowl and let it cool slightly. Once cooled, stir in the cream cheese, shredded provolone cheese, and chopped chives until well combined.

2. Prepare the Chicken: Preheat your oven to 375°F. Using a sharp knife, carefully cut a wide pocket into each chicken breast, taking care not to cut all the way through. Stuff each breast with the prepared mushroom filling, securing with toothpicks as needed.

3. Season the Chicken: In a small dish, combine the kosher salt, onion powder, garlic powder, paprika, and ground black pepper. Generously sprinkle this seasoning mix over each of the stuffed chicken breasts, ensuring even coverage.

4. Cook the Chicken: Heat 2 tablespoon of olive oil in a large skillet over medium-high heat. Add the stuffed chicken breasts and sear for 3-4 minutes on each side until golden brown, but not fully cooked through. Transfer the skillet (with the chicken) to the preheated oven and bake for 20-25 minutes, or until the internal temperature of the chicken reaches 165°F.

5. Serve and Enjoy: Once the Mushroom-Stuffed Chicken is cooked, remove the toothpicks and let the breasts rest for a few minutes. Serve the juicy, flavorful chicken alongside your favorite side dishes.