Preheat oven to 300° degrees.
Melt the butter in a small bowl in the microwave for about 30 seconds or on the stove top in a small sauce pan. Stir in the Sriracha sauce to combine.
Add the cereal, pretzels, crackers and nuts to a large bowl. Pour the Sriracha sauce and butter mixture over the mix, along with a large pinch each of salt and pepper, and toss to evenly mix.
Line two large baking sheet pans with aluminum foil or parchment paper and divide the snack mix between each pan. Bake for 15 minutes and stir the mix, then bake for another 10-15 minutes or until the mix is dry (no longer sticky), but be sure to take it out before it burns.
Let cool before serving. Store at room temperature in large ziploc bags or in a covered bowl. Can be made ahead and kept for up to 2 weeks.