Preheat your oven to 350°F (175°C) and grease a 9x13-inch casserole dish.

Boil a large pot of salted water, add pasta, and cook until al dente (7-8 minutes). Drain and set aside.

In a mixing bowl, combine shredded chicken, drained pasta, cheddar cheese, sour cream, minced garlic, cream of chicken soup, and milk. Season with salt and pepper.

Pour the mixture into the greased casserole dish and spread evenly. Sprinkle breadcrumbs on top if desired.

Bake in the preheated oven for 30-40 minutes, until bubbly and golden brown.

Let the casserole rest for 5-10 minutes before serving.