Preheat your oven to 250°F (120°C) and line a large baking sheet with parchment paper.
In a mixing bowl, combine Rice Chex, Corn Chex, Wheat Chex, mini pretzels, mixed nuts, holiday M&M's, and popped popcorn.
In a separate bowl, melt the unsalted butter and whisk it with Worcestershire sauce, garlic powder, onion powder, smoked paprika, cayenne pepper, and a pinch of salt.
Pour the buttery mixture over the dry snacks and gently fold until all components are coated.
Spread the Chex mix evenly on the baking sheet and bake for about 1 hour, stirring every 15 minutes.
Remove from the oven and allow to cool completely on the baking sheet.
Transfer to an airtight container or serve in a festive bowl.
Notes
For an extra festive flair, serve in a decorative bowl or package in small bags tied with ribbons.