Add the flour to a dish and the bread crumbs to another dish. In third dish, beat the egg.
Heat air fryer to 350 degrees F. Season the chicken all over with salt. Working with 1 piece at a time, coat chicken with flour, tapping off excess. Dip chicken into egg, letting excess drip off, then add to dish with bread crumbs, pressing so crumbs adhere.
Coat both sides of chicken with the cooking spray, then add to air fryer in a single layer, in batches if necessary. Cook 15 min., turning chicken pieces over halfway through. Increase temperature to 400 degrees F and cook another 4-5 min., until golden brown and cooked through. Remove chicken from air fryer and season with salt to taste.
Meanwhile, in a large bowl, toss the greens with the oil and vinegar. Season with salt and pepper to taste. Serve chicken with salad.
Tip: To cook in the oven, set a wire rack inside a rimmed baking sheet. Lightly coat with cooking spray. Place breaded chicken pieces on rack, spaced apart, and coat tops with cooking spray. Bake at 425 degrees F for 30-35 min., until cooked through.