Toss the popcorn and nuts together in a large roasting pan in one layer. Alternately, you can use two 9-by-13-inch pans. Set aside while preparing the caramel coating.Melt the butter in a large heavy saucepan over low heat. Stir in the brown sugar, salt, and maple syrup.Bring the butter mixture to a boil, stirring constantly. Insert a candy thermometer into the pan, without the tip touching the bottom of the pan. Boil the mixture slowly, without stirring, until the temperature reaches the soft crack stage, about 285 F. This could take at least 45 minutes, but watch thermometer temperature carefully. Meanwhile, preheat the oven to 250 F.When the temperature of the mixture is reached, immediately remove from the heat and stir in the baking soda and vanilla.This will cause the mixture to briefly foam up. Stir the mixture and then immediately pour evenly over the popped corn in the roasting pan.Using 2 wooden spoons or rubber spatulas, quickly mix to coat all the popcorn and nuts. Spread the coated popcorn evenly in the pan. Bake at 250 F for 15 minutes, remove from the oven and stir well. Return to oven for another 15 minutes.Turn the caramel corn out onto non-stick foil or parchment-lined baking sheets in a single layer. Cool completely, then break apart to separate any pieces that have stuck together.Melt the chocolate chips in the microwave in 30 second intervals, stirring after each interval until melted. Drizzle the melted chocolate over the cooled caramel corn. Cool the reindeer munch completely before storing.Store in airtight containers or wrap up in cellophane bags for gifts.
