Preheat oven to 350°F. Line a 15x21-inch sheet pan (or 2 smaller sheet pans) with foil and grease with cooking spray.
Add Rice Chex, Corn Chex, and mixed nuts to the prepared sheet pan.
In a heavy, medium pot, add the butter (cut into individual tablespoons), packed brown sugar, and corn syrup. Place over medium to medium-high heat and stir slowly but constantly, until butter is melted. Once melted, continue to stir until the mixture comes to a rapid boil. Boil for exactly 1 minute, stirring constantly, and remove from heat. Add in baking soda and salt. Pour over the cereal on the sheet pan and, working quickly, stir until cereal and nuts are coated in the mixture.
In a small bowl, combine cinnamon and granulated sugar and stir. Sprinkle over cereal mixture.
Bake for 5 minutes, remove from the oven, and toss using a metal spatula. Return to the oven and bake for 3 more minutes. Remove from oven and let cool.
Once the mixture has cooled, sprinkle the tart cherries over the cereal. Break up the yogurt pretzels and add. Toss everything together, breaking up the cereal mixture as needed.
Video
Notes
Storage: Store leftovers in an airtight container at room temperature for up to a week. For longer storage, keep in the fridge for up to two weeks.