Preheat the oven to 400 degrees. Line a 15x10 inch pan with foil, spray with nonstick cooking spray. Cube the chicken into nugget size pieces or a little bigger. On a plate, mix the cornflakes, paprika, salt and pepper. On another plate, beat the egg until thoroughly mixed. Dip the chicken pieces into the egg, then the cornflake mixture. Place the chicken onto the pan and drizzle with the butter.
Bake twenty minutes or until brown on top, turning once. Please check to make sure they are done, as different breasts are of different thicknesses.