Chex mix is meant to be crunchy so to prevent a soggy snack , remember three things - stir, bake, cool. By stirring the seasoning into the dry ingredients, you will prevent the buttery mixture from pooling on one side of the pan. By baking, you allow flavors to soak up into the dry ingredients and crisp to perfection. By cooling before storing, you reduce the likelihood of it turning soggy in the storage container. If you do end up with a soggy Chex mix, troubleshoot by baking for another 10-15 minutes to see if this will help turn it crunchy.