Preheat the oven to 350°F. Grease a 10-inch square baking dish with butter or cooking spray.
Place the potatoes in a large pot and cover them with water. Bring the pot to a boil and cook the potatoes until they are fork-tender, about 10-15 minutes. Then, drain the potatoes and return them to the hot pot.
While the potatoes are cooking, steam or roast the broccoli until it is hot and barely softened. Make sure to drain any liquid from the broccoli. Cook the bacon until it’s crispy, then chop or crumble it and set it aside.
Now, return the pot with the potatoes to a warm (but turned off) burner. Smash the potatoes with a potato masher until they are a nice consistency. Then, add in the butter, sour cream, salt, pepper, garlic, and paprika. Give it a good stir to combine all the flavors.
Next, add the cooked broccoli, chopped chicken, bacon, and 1 cup of cheese to the pot. Mix everything together, and then transfer the mixture to the prepared baking dish. Sprinkle the remaining cheese over the top.
Bake for 20-25 minutes, until the cheese has melted and the casserole is heated through.
Serve hot and enjoy the comforting flavors of this delicious casserole!