Cook broccoli as directed on package. Drain; cover to keep warm.
Meanwhile, place 1 chicken breast half, boned side up, between 2 pieces of plastic wrap or waxed paper. Working from center, gently pound chicken with flat side of meat mallet or rolling pin until about 1/4 inch thick; remove wrap. Repeat with remaining chicken breast halves.
In shallow pan, combine flour, salt and pepper. Coat chicken with flour mixture.
Melt margarine in large skillet. Add chicken; cook 10 to 12 minutes or until chicken is fork-tender and juices run clear, turning once.
Place pineapple slice on each chicken breast half. Top each pineapple slice with 1/4 of broccoli spears and 1 cheese slice. Cover; cook an additional 1 minute or until cheese is melted.