Preheat Oven – Preheat oven to 375°F (190°C).
Season Chicken – Rub chicken breasts with olive oil, salt, pepper, and garlic powder.
Sear Chicken – In a skillet over medium-high heat, sear chicken for 3-4 minutes per side until golden. Remove and set aside.
Cook Bacon & Mushrooms – In the same skillet, cook bacon until crispy, then remove. Sauté mushrooms until tender.
Make Sauce – Lower heat, add heavy cream and sour cream, stirring until smooth. Mix in half the cheeses.
Assemble – Place chicken in a baking dish, pour sauce over, and top with remaining cheese and bacon.
Bake – Bake for 15-20 minutes until cheese is bubbly and chicken is cooked through (165°F internal temp).
Garnish & Serve – Sprinkle with green onions and serve hot.