Melt margarine in small saucepan. Add brown sugar, honey and salt and bring to a boil over medium heat, stirring constantly. Boil for 5 minutes, stirring from time to time. Add in vanilla and remove from heat. Quickly pour sugar mixture over popcorn and nuts, stirring with a spatula until well-coated.
Spread mixture in a single layer on a lined baking tray. Bake for 30 minutes, stirring at least once.
Cool on wire racks and break into chunks.
Place chocolate in a mixing bowl, and melt in a bain-marie. Drizzle melted chocolate over the chunks. Allow to cool and for chocolate to set before storing in an air-tight container.