Preheat oven to 250 degrees F.
In a large bowl, add the Chex cereals, pretzels, Gardettos, and nuts. Mix together.
In a smaller bowl or large measuring cup, melt the butter. Add the Worcestersshire, soy sauce, seasoned salt, garlic powder, onion powder, optional cayenne, and the optional mustard powder. Mix well.
Pour over the cereal mixture and toss to coat well; this will take a few minutes for a good coating.
Place into a large broasting pan or divide into sheet pans and place in the preheated oven. Bake for one hour, stirring mixture every 15 minutes. Remove from oven and allow to cool for 15 minutes. (May be placed on paper towels to absorb any excess butter.)
To store, add the room-temperatoure chex mix to a large container (or several) or Ziploc bags.
Find it online: https://frugalhausfrau.com/2025/12/13/favorite-chex-mix/