Preheat the oven to 350 degrees F (175 degrees C). Coat a 9x13-inch baking dish with cooking spray.

Place chicken in the prepared baking dish. Combine soup, sour cream, and sherry in a bowl; pour or spoon over chicken. Season with salt and black pepper.

Combine crushed crackers and poppy seeds; sprinkle over chicken. Season with salt and black pepper. Drizzle melted butter over cracker layer. Cover baking dish.

Bake in the preheated oven for 30 to 45 minutes, uncover for the last 5 minutes. Let stand before serving, 3 to 5 minutes.