In medium bowl, place 3 cups popcorn mixture. In 1-quart saucepan, melt chocolate chips over low heat, stirring constantly. Drizzle chocolate evenly over 3 cups popcorn mixture; toss gently to thoroughly coat popcorn. Spread in single layer on foil or cooking parchment paper. Cool about 2 hours or until chocolate is firm. Add chocolate-covered popcorn mixture to remaining popcorn mixture; toss gently to combine. Store tightly covered.