Whisk the melted butter, brown sugar, maple syrup, cinnamon, cayenne, cardamom and salt in a large bowl.
Add the nuts, pretzels, and crackers and toss to coat.
Spread the mixture onto a parchment paper lined baking sheet and bake for 15-20 minutes, stirring once halfway. The mixture will still be slightly wet-looking and will dry out as it cools.