Blend the last 4 ingredients on high for 30 seconds, stir, bring to a full boil - cooking approx 2 minutes. Then stir in the baking soda until well dissolved.
Put the popcorn in a large paper grocery bag, add nuts if desired. Pour the syrup over the popcorn in the bag, roll up bag and shake. Microwave 1 1/2 minutes. Shake then place on a cookie sheet to cool.