In a double boiler, combine the chocolate chips, butter, coffee liqueur, instant espresso, vanilla and nutmeg. Heat until the chocolate melts, stirring the mixture until smooth and blended.
Put the confectioners' sugar in a large resealable bag. Combine the rice cereal and popcorn in a large bowl.
While stirring, slowly pour the melted chocolate mixture over the cereal mixture; mix until everything is well coated. Transfer to the resealable bag with the confectioners' sugar and shake the bag to coat everything with the sugar. Store in an airtight container or clean resealable bag.