Preheat Oven: Set your oven to 375°F (190°C).
Season the Chicken: Pat chicken breasts dry and season with salt, pepper, garlic powder, and onion powder.
Sear the Chicken: Heat olive oil in a large oven-safe skillet over medium-high heat. Add chicken breasts and sear for 2-3 minutes per side until golden brown. Remove and set aside.
Sauté the Mushrooms: In the same skillet, add butter and sliced mushrooms. Cook for 3-4 minutes until softened. Stir in minced garlic and cook for another 30 seconds.
Make the Sauce: Reduce heat to low, then stir in heavy cream (or sour cream). Let it simmer for 1-2 minutes.
Assemble & Bake: Place the chicken back in the skillet (or transfer to a baking dish). Spoon the mushroom sauce over the chicken and sprinkle mozzarella, cheddar, and Parmesan cheese on top.
Bake: Transfer to the oven and bake for 20-25 minutes or until the chicken is fully cooked (internal temperature 165°F/75°C).