Wash the kale leaves and pat them dry using a clean towel or paper towels. Separate the leaves from the stem. Discard the stem. Tear the leaves into bite-sized pieces.
Transfer the kale leaves to a medium-sized bowl.
Add oil, salt, pepper, and garlic powder over kale. Massage it in until all the leaves are coated.
Preheat the air fryer and set it to 375°F.
[Optional step] Line the air frying tray with parchment paper.
Transfer the kale leaves over the parchment paper – don't overcrowd them. Depending on the size of your airfryer, you may have to make them in batches.
Place the air fryer tray in the air fryer and cook at 375°F. Set the timer for 5 minutes.
Stir around the 2-minute mark and continue to cook till kale chips have nicely browned and turned crisp. [Note: If using an oven-style air fryer, rotate the tray and if using the basket-style air fryer, shake the basket to ensure even cooking]
Transfer the kale chips to a baking tray without overcrowding them. Allow it cool for 5-10 minutes before serving.
When the kale chips are completely cooled, store them in an air-tight container at room temperature for a week. If they lose their crispiness, toss them in the air-fryer for a minute or so, to get their crunch back.