Preheat oven to 200 degrees F.
Divide the nuts, cereals and pretzels between two or three large baking pans. You’ll need high sided pans to allow for stirring the mixture while baking. Use three pans if needed and rotate the pans while baking.
Combine the butter, Worcestershire, celery salt, garlic salt and chili powder is a large, microwave safe bowl. Microwave on medium power for 2 minutes, then stir. Repeat until all the butter is melted. Mix well. Using a large spoon or ladle, drizzle the butter mixture over the cereal and nuts, stirring the butter mixture as you go to distribute all the spices that may settle in the bottom of the bowl.
Bake for 3 hours gently stirring every 15 minutes taking care not to crush the cereal. Use a large flat spatula if you have one, pulling up from the bottom of the pan to ensure all pieces are well coated in the butter mixture. Rotate the pans if needed.
Turn the warm mixture out onto paper towels spread over wax or parchment paper. Cool completely then transfer to air tight containers to store in a cool location. Mixture keeps up to two weeks.