Preheat the air fryer to 300ºF (149ºC) for at least 3 minutes, or according to your manufacturer's instructions.
Add the Chex cereals, mixed nuts, pretzels, and the mix-ins of your choice into a very large bowl.
In a separate microwave-safe bowl, add the butter. Heat in 30-second intervals until completely melted.
Add the Worcestershire sauce, seasoned salt, garlic powder, and onion powder to the melted butter and stir well to combine.
Pour half of the melted butter mixture over the cereal and mixins, and toss well to coat. Add the remaining half of the butter mixture, and toss well until everything is evenly coated.
Transfer the prepared Chex Mix to your air fryer basket, spreading it out evenly.
Cook for 6-8 minutes, shaking the basket every 2 minutes to help promote even cooking.
Once the chex mix has some lightly browned bits, remove from the air fryer allow to cool (I like to spread it out on a parchment-lined tray).
Once completely cooled, serve immediately in a large bowl OR transfer to an airtight container for storage.
Keeps well at room temperature for 1-2 weeks.
Notes
Storage: Chex Mix should last 1-2 weeks in an airtight container at room temperature.
Variations
Gluten free: Swap the pretzels for gluten free pretzels, and use the gluten-free types of Chex cereal (rice and corn). Choose a gluten-free option for a mix-in, or use more cereal, pretzels, or mixed nuts.
Ranch: Use 1.5-3 tablespoons of ranch dressing mix (or homemade ranch seasoning) and omit the garlic powder, onion powder, and seasoned salt.
Buffalo ranch: Omit the garlic powder and onion powder. Use 2-3 tablespoons of buffalo ranch seasoning, and an optional 1.5-3 tablespoons of ranch dressing mix.
Cheese: Add 2-4 tablespoons of white or cheddar cheese powder to the melted butter mixture.
Dill Pickle: Add 2-3 tablespoons of dill pickle seasoning to the butter mixture.