Preheat oven to 250 degrees. Combine brown sugar, corn syrup or honey, butter, and pumpkin pie spice in a pan on the stove. Heat until butter is melted and mixture starts to bubble.
Remove from heat and add orange extract and baking soda. Pour over popcorn and stir until mixture is evenly distributed. Mix in nuts. Spread on a foil-lined cookie sheet. (You may need to use two cookie sheets and take turns baking them in the oven).
Put in the oven for 30 minutes, stirring every 10 minutes. Remove from oven and let cool slightly.
Transfer the popcorn to a large sheet of parchment, waxed paper, or foil sprayed with non-stick cooking spray. Drizzle melted chocolate over the top. Let harden, then transfer to airtight container.