In a large shallow roasting pan combine popcorn and nuts. Place in 250* F. oven while preparing glaze. In heavy 2 quart saucepan stir sugar, corn syrup, margarine and salt.
Stirring constantly, bring to boil over medium heat. Without stirring, boil 5 minutes. Remove from heat, stir in vanilla and baking soda; pour over popcorn mixture, stirring to coat. Bake in 250* F. oven, stirring occasionally, for 1 hour. Cool; break apart and store tightly covered. 4 quarts.