Preheat your oven to 350°F (175°C). Lightly grease a 9x13-inch baking pan or any similarly sized oven-safe dish.
In a large saucepan of boiling salted water, cook the egg noodles until just firm to the bite (al dente), as they will continue to soften while baking. Drain and set aside.
In a sizable mixing bowl, combine the condensed chicken soup, sour cream, milk, garlic powder, onion powder, salt, and pepper. Whisk until a smooth and creamy consistency forms.
Add the drained noodles, shredded chicken, half of the shredded cheddar, and half of the crumbled bacon to the bowl. Stir thoroughly until the ingredients are well mixed and evenly coated in the sauce.
Pour the mixture into the prepared baking dish, spreading it out evenly. Sprinkle the remaining cheddar and bacon evenly over the top.
Cover the dish with aluminum foil and bake for 20 minutes. Remove the foil and continue baking for an additional 10 to 15 minutes, or until the cheese is fully melted and the casserole is bubbling around the edges.
Remove from the oven and allow the dish to rest for about 5 minutes before serving. Garnish with chopped scallions, if desired.