Preheat oven to 350 degrees F. Prepare the brownie mix according to package directions for fudgy brownies. Pour into a greased 13x9" rectangular baking pan and bake for 19-20 minutes or until a toothpick inserted near the center comes out clean or with moist, not wet, crumbs. Do not bake too long as the brownies MUST be fudgy in order to make the bombs work. Cool completely.
While brownies cool, make your Mint Oreo truffles. In a large bowl, combine the Mint Oreo crumbs, cream cheese, and 1/2 tsp mint extract with a rubber spatula until blended and moistened; fold in 1 cup of the Andes mint chips. Roll Tablespoon-sized balls of Mint Oreo truffles and place them on a foil-lined baking sheet. Freeze for at least 30 minutes.
Cut the brownies into 24 equal pieces, making sure to trim off the edges as they're too crusty and hard to work with. Take a brownie square and gently flatten it in the palm of your hand. Wrap the brownie around the Oreo truffle, pinching and rolling the brownie in your hands to completely enclose the truffle. Place the brownie bombs onto the baking sheet. Freeze for approx. 30 minutes or until solid and firm.
Melt the chocolate candy coating according to package directions or until smooth and melted; gently fold in the remaining mint extract. Dip each brownie bomb into the chocolate coating, coating it completely and allowing excess to drip off. Return to the baking sheet with a fork and sprinkle with remaining Andes mint chips, if desired.