Preheat oven to 300 degrees F. Line a baking sheet with parchment paper.
In a large mixing bowl, add the cereal, pretzels, crackers, and nuts. Toss to combine.
In a small bowl, whisk together the barbecue sauce, butter, ½ teaspoon of salt, and pepper.
Pour sauce over the snack mixture, and toss to coat. Spread the mix in an even layer onto the prepared baking sheet. Bake for 45 minutes, stirring the mixture every 10 minutes.Remove from the oven and cool completely.
Once cool, pour the snack mix into a large bowl or resealable container. Add in the chili powder, garlic powder, and salt. Stir until the mix and evenly coated with the spices. Serve immediately or store in an airtight container up to one week.