One at a time, dredge the chicken pieces first in the egg mixture, and then in the cornflake mixture, being sure to coat the entire chicken piece. Place the chicken piece on the baking sheet which has been coated with cooking spray. Repeat for each chicken piece until you have breaded every chicken piece. Be sure to space the chicken pieces about 1 inch apart from eachother on the baking sheet. Overcrowding the baking sheet will cause the chicken nuggets to become soggy, and will not allow air to circulate around the chicken nugget (which is needed to make them crispy).