Mix melted butter, brown sugar, almonds, coconut, and crushed cereal together in a bowl until thoroughly combined and crumbly. Press half the mixture into a 9x13-inch dish; reserve remaining mixture.
Smooth the ice cream in an even layer over the crust. Sprinkle top with remaining cereal mixture.
In a saucepan, combine the chocolate chips, corn syrup, and evaporated milk over low heat until the chocolate chips have melted; stir the mixture until combined and smooth. Heat to a bare simmer, and cook, stirring constantly, until the syrup has thickened, 5 to 10 minutes. Allow to cool for about 10 minutes, then drizzle syrup over the top of the cake. Freeze the cake until firm, at least 2 hours; remove about 15 minutes before serving.
