Easy Creamy Chicken Casserole

1 sleeve buttery round crackers (such as Ritz®), crushed

2 tablespoons butter, melted

4 cups water

1 (32 fluid ounce) container chicken stock

salt and ground black pepper to taste

3 skinless, boneless chicken breast halves, cubed

1 (24 ounce) container sour cream, or to taste

1 (26 ounce) can condensed cream of chicken soup

Preheat an oven to 350 degrees F (175 degrees C). Mix the crackers and melted butter together in a bowl; set aside.

Bring water and chicken stock to a boil in a pot over high heat. Season with salt and black pepper. Add the chicken. Reduce heat to a simmer, and cook, stirring occasionally, until chicken is no longer pink in the center, 5 to 7 minutes. Drain the chicken; set aside. Whisk together the sour cream and cream of chicken soup in a large bowl. Stir in the chicken, then transfer the mixture to a 9x13-inch baking dish. Sprinkle the cracker mixture on top.

Bake in the preheated oven until bubbly, 25 to 30 minutes.