Prepare cake mix according to package directions for a 13x9-inch baking pan. Cool in pan on a wire rack. Line baking sheets with waxed paper; set aside.
Remove cooled cake from pan and crumble into an extra-large bowl. Add the Mexican Chocolate Frosting. Beat with a mixer on low until combined. Using a small scoop, drop into about thirty-eight 1 1/2-inch mounds onto prepared baking sheets; roll each mound into a ball. Freeze balls 30 minutes.
In a small microwave-safe dish heat 1 oz. of the candy coating on medium for 1 minute or until melted and smooth, stirring once. Dip one end of each lollipop stick into melted coating and poke stick into a ball (coating helps the cake ball stay on the stick). Freeze cake pops 30 to 60 minutes or until cake balls are firm.
In a small saucepan combine the remaining candy coating and the chopped chocolate. Heat over medium-low heat until mixture is melted and smooth, stirring frequently. Working in batches, dip cake balls into melted chocolate mixture. Allow excess to drip off. Poke the ends of the lollipop sticks into plastic foam or florist's foam to suspend the pops until chocolate sets.
In a small bowl combine cocoa powder and chile powder; sift mixture over pops before chocolate sets. After chocolate sets, transfer pops to airtight storage containers. Cover and store in the refrigerator up to 1 week. Let stand at room temperature at least 30 minutes before serving.
Mexican Chocolate Frosting
In a small bowl stir together the 2 tablespoons milk, espresso coffee powder or instant coffee crystals, vanilla, and ground cinnamon. In a small heavy saucepan melt Mexican chocolate over medium-low heat, stirring constantly; remove from heat and set aside to cool slightly. In a medium mixing bowl beat butter with an electric mixer on medium speed until smooth. Gradually add 3/4 cup of the powdered sugar, beating well. Slowing beat in milk mixture. Beat in melted chocolate. Gradually beat in remaining 2 cups powdered sugar. If needed, beat in additional milk, 1 teaspoon at a time, to make a spreadable frosting.