Step 1: Preheat your oven to 250°F (120°C).
Step 2: In a very large roasting pan or two large baking sheets, combine the Corn Chex, Rice Chex, Wheat Chex cereals, pretzels, mixed nuts, and bagel chips. Make sure the ingredients are spread out as much as possible for even seasoning.
Step 3: In a separate small microwave-safe bowl, melt the unsalted butter. Stir in the Worcestershire sauce, garlic powder, onion powder, and seasoned salt until well combined.
Step 4: Pour the melted butter mixture evenly over the cereal mixture in the roasting pan. Gently stir with a large spoon or spatula until all ingredients are lightly coated.
Step 5: Bake for 1 hour, stirring the mixture thoroughly every 15 minutes to ensure even baking and to prevent burning.
Step 6: After baking, remove the Chex Mix from the oven. Spread it out onto several layers of paper towels or a clean kitchen towel to cool completely. This will help absorb any excess oil and enhance crispiness.
Step 7: Once completely cooled, store the homemade Chex Mix in an airtight container at room temperature for up to 2-3 weeks. Enjoy your delicious snack!