Put the popcorn into a large bowl and set aside. Line a large baking sheet with parchment paper or a silpat liner; set aside. Sift together the baking soda and nutmeg in a small bowl; set aside. Add the vanilla extract, almond extract, butter extract, and rum extract to a small bowl; set aside.
Cook the butter, sugar, molasses, water, and salt in a medium-sized, thick-bottomed saucepan over medium heat until the temperature reaches 305F (hard crack stage), stirring occasionally. Carefully stir in the mixture of extracts and then the baking soda/spice mix; pour the toffee over the popcorn/nut mixture.
Use two heat-safe rubber spatulas to toss the popcorn around to distribute the toffee throughout. Spread the popcorn out onto the prepared baking sheet.
Let the popcorn cool and then break it apart; store in an airtight container at room temperature.
Making This on a Hot and/or Humid Day: If it’s a hot and/or humid day and the butterbeer popcorn is too sticky, you can dry it out in the oven. To do so, leave the butterbeer popcorn on the baking sheet and bake it in a 200F oven for 20 to 30 minutes, tossing it every 10 minutes.