Preheat the oven to 300 degrees Fahrenheit (120 degrees Celsius), and line a large baking sheet with parchment paper or use a non-stick baking sheet.
In a large mixing bowl, combine the wheat Chex cereal, rice Chex cereal, oyster crackers, cashews, almonds, and mini pretzels. Toss gently to mix, and set aside.
4 cups wheat Chex cereal, 4 cups rice Chex cereal, 2 cups oyster crackers, 2 cups raw cashews, 2 cups raw almonds, 3 cups mini pretzels
In a microwave save bowl melt the salted butter (or in a saucepan). Once melted, stir in the za'atar, garlic powder, onion powder, dried oregano, sea salt, cayenne pepper, and honey. Mix well until all the spices are fully incorporated into the butter.
8 Tablespoons salted butter, 3 Tablespoons za'atar, 2 teaspoons garlic powder, 1 teaspoon onion powder, 2 teaspoons dried oregano, 1/2 teaspoon sea salt, 3/4 teaspoon cayenne pepper, 2 Tablespoons honey
Pour the seasoned butter mixture over the cereal, crackers, and nuts. Use a spatula or large spoon to gently toss and coat all the ingredients evenly with the seasoning. Mix for a few minutes to really make sure the butter mixture coats everything.
Spread the mixture evenly onto the prepared baking sheets.
Bake in the preheated oven for 30-35 minutes, stirring every 15 minutes to ensure even toasting and coating of the mixture.
Remove from the oven, and let the Spicy Za'atar Chex Mix cool completely on the baking sheet.
Once cooled, transfer the mix to an airtight container for storage. Enjoy this flavorful snack at any time!