Preheat air fryer to 375°F.
Rinse and dry your kale, then remove leaves from stems and tear into small pieces, discard stems.
Add kale leaves to a large mixing bowl, drizzle with oil and massage gently. Add your ranch seasonings and your dijon mustard and toss to combine.
Spread the kale leaves in a single layer along the bottom of your air fryer basket (you will likely need to do multiple batches). Try to avoid the leaves touching to get the crispiest kale chips!
Air fry for about 5 minutes or until kale is crispy. Note: as all air fryers are different I'd recommend checking the kale chips a little before the 5 minute mark. You want your kale chips to be crispy but not burnt!
Once your kale chips are done, remove them from the air fryer and let cool slightly – chips will crisp up even more the longer you allow them to sit.
These are best eaten fresh so enjoy immediately or store in a sealed container for 2-3 days!