Toss Chex, bugles and pretzels together in a large bowl.
Add butter, brown sugar and corn syrup in a medium saucepan and cook over medium heat, stirring occasionally until butter is melted, the sugar is dissolved and the mixture comes to a boil.
Remove from heat and stir in vanilla and baking soda.
Pour mixture over Chex mix and toss to coat.
Pour mixture onto a large jelly roll size baking sheet lined with silicone liner, parchment paper or non-stick aluminum foil. You can use 2 baking sheets if needed. Just make sure mixture is a single layer.
Bake for 10-15 minutes, checking roughly every 5 minutes. Mixture will be bubbly.
Remove from oven and allow to cool.
Once cool, break into pieces and store in an airtight container.