Tear kale leaves into large chip-sized pieces. Transfer to a medium bowl.
Spray with zero-calorie nonstick cooking spray and drizzle with lemon juice. Toss to combine.
Season with salt and black pepper, then add any optional seasonings. Toss to combine.
In an air-fryer basket, arrange kale in a single layer.
Cook at 350°F until edges start to brown, 3-5 minutes.
Transfer kale to a sheet pan and let cool in a single layer. Kale will continue to crisp as it cools.