Heat oven to 250 degrees. Melt butter or margarine in a shallow pan (sheet cake pan or broiler pan) over low heat. Stir in Worcestershire sauce and seasoned salt. Add 6 cups assorted Chex (Wheat, Corn & Rice combined equally or any way you like). Add 2 cups salted nuts and 1 cup of pretzels. Mix over low heat until all the pieces are coated. Heat for 45 minutes in the oven, stirring every 15 minutes. Spread out on absorbent paper to cool.