Preheat the oven to 250 degrees F. Generously spray a baking sheet with cooking spray.
Mix the chopped pecans and warm popcorn on the prepared baking sheet. Place in the oven while preparing the syrup.
Combine the brown sugar, butter and honey in a heavy medium saucepan. Whisk over medium-low heat until the sugar dissolves and the butter is completely melted. Increase the heat to high and boil for 4 minutes, stirring constantly. Remove from the heat, add the salt, chipotle powder and baking soda and mix to evenly incorporate. Slowly pour the syrup over the popcorn-pecan mixture. Stir gently to make sure the popcorn and nuts are completely coated.
Bake until the caramel is dry and has hardened, about 1 hour. Let cool before serving.