Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch cake pan with cooking spray.
Combine chocolate cake mix, water, eggs, and oil in a large bowl; beat with an electric mixer on medium speed until smooth, about 2 minutes. Pour batter into the prepared cake pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 26 to 31 minutes.
Mix 1 cup evaporated milk, 1 cup sugar, and marshmallows together in a large pot; cook and stir over medium-low heat until marshmallows are melted, about 5 minutes. Stir in coconut. Pour coconut mixture over hot cake.
Combine 1/2 cup evaporated milk, butter, and 1/2 cup sugar in a saucepan; bring to a boil, stirring constantly. Fold in chocolate chips and almonds. Spread over coconut layer.
Cool cake until coconut layer and chocolate layer are set, about 30 minutes.