Preheat the oven to 450 degrees F (230 degrees C). Coat a 9- x 1-inch baking dish with cooking spray.

Combine potatoes, olive oil, garlic powder, onion powder, paprika, black pepper, and 1/2 teaspoon of salt in a large bowl; toss until evenly coated. Transfer to the prepared baking dish.

Bake in the preheated oven until potatoes are golden and fork-tender, 25 to 30 minutes. Set aside.

Meanwhile, cook bacon in a large skillet over medium, turning occasionally, until crisp, 10 to 15 minutes. Drain bacon on a paper towel-lined plate; remove and reserve 1 tablespoon drippings from the skillet. When bacon is cool enough to handle, finely chop, and set aside (about 1/2 cup).

In the same large bowl, combine chicken, cream cheese, water, scallions, hot sauce, 1/4 cup of the bacon pieces, reserved bacon drippings, 1 1/2 cups cheese, and remaining 1/2 teaspoon salt.

Fold chicken mixture into the potatoes in the casserole until well combined. Sprinkle with remaining 1/2 cup shredded cheese.

Bake until cheese is melted, 10 minutes longer.

Set an oven rack about 6 inches from the heat source and switch to the oven’s broiler function. Broil on high for 3 minutes or until cheese is bubbling and brown in spots.

Garnish with remaining bacon (about 1/4 cup) and additional scallions. Serve with sour cream.