Preheat oven to 300°F (150°C). Line a baking sheet with parchment paper.
Mix dry ingredients (cereal, pretzels, chips, and nuts) in a large bowl.
In a small saucepan, melt butter, then stir in brown sugar, maple syrup, cinnamon (if using), and a pinch of salt. Heat until bubbly.
Pour the warm syrup mixture over the dry ingredients. Toss to coat everything evenly.
Spread snack mix onto the baking sheet in a single layer.
Bake for 40–50 minutes, stirring every 15 minutes until lightly toasted and caramelized.
Let it cool completely, then stir in any optional add-ins.