Preheat the oven to 250°F. Line a large baking sheet with parchment paper if desired.
Add the Chex cereal, pretzels, mini club crackers, and honey teddy grahams to a large mixing bowl. Gently toss to combine.
In a small bowl, whisk together the granulated sugar, light brown sugar, cinnamon, maple syrup, kosher salt, and melted butter until well combined.
Drizzle the maple cinnamon mixture over the cereal mixture, gently tossing as you drizzle. Continue tossing until the coating is distributed as evenly as possible.
Spread the coated snack mix into an even layer on a large baking sheet. Bake at 250°F for 30–40 minutes, stirring every 10 minutes to help everything cook evenly.
Remove the party mix from the oven and allow it to cool completely on the baking sheet. The snack mix will become crunchier as it cools.
Once completely cooled, transfer the party mix to an airtight container or serve immediately.