The main reason you might end up with soggy kale chips is they aren't completely dry before they are baked! It's very important to let your kale dry completely after washing and before adding the olive oil. If any water remains, it will turn to steam in the oven and leave behind a sad soggy mess.  You also want to make sure to bake it on a low temperature for a long time, to dry the kale out completely. Lastly, when baking this kale chip recipe in an oven, you want to avoid flavoring it with any liquids like hot sauce or vinegar. That's actually why I didn't include those types of flavoring agents because they make chips soggy.