Preheat your oven to 250°F. Make sure a rack is in the center of the oven, as well.

Using a microwave safe bowl, melt the butter and the oil together in the microwave.

Remove the bowl from the microwave. Which in Worcestershire sauce and salt.

Using a spatula, fold in the Rice Chex, pretzels, and nuts until all pieces are evenly coated. The coating will be light.

Put a wax paper lining on a cookie sheet. Scrape the contents of the bowl out onto the sheet, spreading them evenly.

Bake for 30 to 45 minutes, until the Rice Chex has reached a light brown color. Turn the ingredients once while cooking.

Allow the Chex Mix to cool on a rack. Once cool, serve or store in an airtight container. Chex Mix will last for one week at room temperature in most cases.