Pre-heat the oven to 250°.
In a large rimmed sheet pan mix together the cereals and the mixed nuts.
In a small sauce pan melt the butter and add the brown sugar Worcestershire sauce, Gochujang, onion powder, garlic powder, salt, and sesame seeds.
Allow the mixture to bubble for a minute or so to dissolve the sugar.
Pour over the cereal, and using a spatula, mix thoroughly.
Bake in the preheated oven for 1 ½ hours, stirring thoroughly every 15 minutes or until the snack mix is dry and lightly toasted.
Remove the snack mix from the oven and stir in the pretzel goldfish, peanuts and the sesame sticks.
Allow to cool completely.
If stored in an airtight jar or plastic bags, this will last for several months.