Pound chicken breasts to 1/4 inch thick. In a medium size bowl, stir together mayonnaise, dried dill weed, garlic powder, black pepper, seasoning salt and lemon juice.
Mix well.
Dip chicken breasts in mayonnaise mixture (let excess drip off), then dip in cornflake crumbs to coat well.
Place coated chicken in a lightly greased 9x13 inch baking dish.
Bake in the preheated oven for 20 minutes or until chicken is lightly browned and no longer pink inside.