Bake cake in a 9x13-inch pan according to direction on the package.
While cake is baking, mix condensed milk and hot caramel topping until well blended. When the cake is done and while it's still hot, poke holes in it with a fork or straw. Pour milk mixture over the cake. Allow cake to cool completely. Sprinkle chocolate chips over cake.
In a chilled bowl, whip together heavy cream, powdered sugar and vanilla. Whip on high speed of an electric mixer for 1-2 minutes. Stir in chopped snickers. Spread over cake. Sprinkle chopped peanuts over cake. Drizzle caramel and chocolate sauce on top. Chill.