Preheat the oven to 375 degrees. Coat a baking sheet with cooking spray. Cut the chicken tenders in half crosswise. Mix the flour and cornstarch together in a shallow bowl. In another bowl, beat the egg whites together lightly. Spread the cornflakes out on a plate. Working with 1 piece of chicken at a time, dredge the chicken in the flour mixture. Dip it next into the egg whites, then roll in the cornflakes crumbs coating all sides. Place the chicken pieces in 1 layer on the prepared baking sheet. Bake for 10 minutes, or until the pieces are cooked through.