Preheat the oven to 350 degrees F (175 degrees C). Grease a shallow baking dish with cooking spray.
In one bowl, stir together the cornflake crumbs, bread crumbs, salt, garlic powder, onion powder and paprika. In another bowl, whisk together the evaporated milk, egg, lemon juice and butter using a fork.
Dip the chicken pieces in flour, and shake off the excess. Dip into the milk batter, then into the crumb mixture. Place pieces in a single layer in the greased baking dish. Spray the top of the chicken with cooking spray.
Bake uncovered for 1 hour in the preheated oven, until nicely browned, and juices run clear.
