Reserve ½ cup of frosting in a small bowl for the orange details and tint the larger portion green and the reserved portion orange. Split 6 Oreo cookies into 12 halves to make the hat brims; place a small dab of orange frosting on each half, top with a Hershey's kiss, and add sprinkles before placing on the cupcakes. Refrigerate the assembled cupcakes covered to set the frosting and keep them fresh.