Preheat and prep: Heat oven to 375°F (190°C). Grease a 9x13-inch baking dish with butter or oil.
Soften the cream cheese: In a large bowl, beat softened cream cheese with sour cream and heavy cream until smooth.
A hand mixer helps prevent lumps.
Season the sauce: Stir in ranch seasoning, garlic powder, onion powder, smoked paprika, and a pinch of salt and pepper.
Add the mix-ins: Fold in shredded chicken, half the bacon, green onions, and optional broccoli or cauliflower rice.
Cheese it up: Mix in 1 cup cheddar and 1/2 cup Monterey Jack or mozzarella. Taste and adjust salt and pepper.
Assemble the casserole: Spread the mixture evenly in the baking dish. Top with remaining cheddar and Monterey Jack.
Bake: Place on the middle rack and bake 18–22 minutes, until the edges are bubbling and the cheese is melted.
Finish with bacon: Sprinkle the remaining bacon over the top and bake 3–5 more minutes to crisp.
Rest and garnish: Let rest 5 minutes to set.
Garnish with extra green onions. Serve warm.