Preheat oven to 350°F and lightly grease a 9-inch square casserole dish.
Parboil diced potatoes in salted water for 5 minutes. Drain and set aside.
Layer half the potatoes in dish, then add chicken. Season with ¼ tsp each salt and pepper.
Top with half the bacon, ½ cup cheese, and half the green onions.
Add remaining potatoes, bacon, ½ cup cheese, green onions, and rest of salt and pepper.
Pour cream over the top. Dot with butter.
Cover with foil and bake for 1 hour. Uncover and bake an additional 30 minutes.
Sprinkle remaining ½ cup cheese and bake until melted. Let rest 10 minutes before serving.
