Heat an air fryer to 400ºF. Place the chicken in the basket in a single layer skin-side down. Air fry for 10 minutes. Flip the chicken and air fry until crispy and an instant-read thermometer in the thickest piece registers 165ºF, 12 to 15 minutes more. Meanwhile, drain the potatoes in a colander and pat very dry with towels. Place in a large bowl, add the remaining 1 tablespoon olive oil and 1 teaspoon kosher salt, and toss to coat.