Bring to a boil over high heat, stirring often. Reduce heat to medium-low; cover and simmer 5 min.
Meanwhile, cube chicken. Place in Round Steamer. Cover; microwave on high, 5 min, stirring halfway through, until chicken is cooked. Remove from microwave. Let rest, and leave it covered, 1 min to let heat redistribute.
Place chicken into pan with sauce (discard liquid in steamer). Stir to coat. Top with cheese. Cover 1 min or until cheese has melted.