Preheat oven to 350°F (175°C) and prepare a large baking sheet with a silicone mat.
In a large bowl, combine popcorn, Chex cereal, pretzels, nuts, and potato chips.
In a saucepan, melt butter over medium heat. Add brown sugar and corn syrup, stirring frequently until boiling.
Reduce heat and simmer for 2 minutes without stirring.
Remove from heat, add salt and vanilla carefully, then stir.
Add baking soda and mix vigorously until the caramel becomes light and creamy.
Pour caramel over the mixture and stir well to coat evenly.
Spread onto the baking sheet and bake for 4 minutes, stirring halfway through.
Let cool completely until crisp, then break into pieces.