Preheat the oven to 375 degrees F (190 degrees C). Grease a 9x13-inch baking dish.

Place cereal in a large resealable plastic bag; crush into crumbs. Add garlic salt and seasoned salt; shake mixture together in the bag to combine. Pour crumb mixture out into a shallow bowl.

Beat egg with milk in another shallow bowl. Dip each chicken breast half into milk mixture, then into crumb mixture, coating chicken well with crumbs. Place coated chicken breasts into the prepared baking dish.

Bake in the preheated oven until cereal coating is golden brown, chicken is no longer pink in the center, and juices run clear, about 40 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).