For the chipotle spice blend: Mix together the sugar, chipotle powder, coriander, cumin, lime zest, granulated garlic and 1 1/2 teaspoons salt in a small bowl and set aside.
For the snack mix: Preheat the oven to 350 degrees F. Lightly oil a rimmed baking sheet.
Put the egg white in a large bowl and whisk until frothy. Add the cashews, cereal, corn nuts, pretzels and oyster crackers and toss to coat in the egg white. Add the spice blend and toss to coat again.
Spread the nut mixture evenly on the prepared baking sheet and bake, stirring occasionally, until golden brown, 15 to 20 minutes. Let cool on the baking sheet, then stir in the popcorn and transfer to a large bowl.