Cook Chicken In A Large Skillet Over Medium-High Heat Until No Longer Pink And Juices Run Clear, About 15 Minutes. Meanwhile, Bring Water And Bouillon To A Boil In A Large Saucepan. Stir In Rice, Cover Pan, And Remove From Heat. Let Rice Stand Until Water Is Absorbed, About 5 Minutes. Combine The Cooked Chicken, Tomatoes, And Mushrooms In Saucepan With The Cooked Rice, And Stir Over Medium-Low Heat Until Heated Through. Serve Hot.