Preheat the air fryer to 400°F for 3 minutes while you prep; ensure the basket is clean and dry.
Pat the chicken tenders dry with paper towels and place in a medium bowl.
Whisk lime zest, lime juice, oil, chili powder, smoked paprika, cumin, garlic powder, cayenne, brown sugar, salt, and pepper in a small bowl; pour over tenders and toss to coat evenly.
If using cornstarch, sprinkle it over the coated tenders and toss briefly; arrange tenders in a single layer in the air fryer basket with space between pieces.
Cook at 400°F for 4 minutes, flip tenders with tongs, then cook 3–4 more minutes until internal temperature reads 165°F and edges are golden with tiny blisters.
Transfer to a plate and rest 3 minutes; sprinkle reserved lime zest and chopped cilantro before serving.