Divide popcorn and nuts between 2 ungreased rectangular pans, 13x9". Cook brown sugar, butter, corn syrup and salt over med heat, stirring constantly until bubbly around edges. Continue cooking 5 mins, remove from heat. Stir in baking soda until foamy. Pour over popcorn and nuts, stirring until corn is well coated. Bake uncovered 200, 1 hr, stirring every 15 mins. 300 cal per 1c