Heat The Olive Oil In A Skillet Over Medium Heat. Cook The Chicken Breasts In The Skillet Until No Longer Pink In The Center And The Juices Run Clear, About 10 Minutes. An Instant-Read Thermometer Inserted Into The Center Should Read At Least 165 Degrees F (74 Degrees C). While The Chicken Cooks, Stir The Chicken Broth, Orange Marmalade, And Ranch Dressing Mix Together In A Bowl; Pour Over The Chicken. Add The Cornstarch To The Liquid In The Skillet And Stir. Bring The Mixture To A Low Boil, Reduce Heat To Medium-Low, Place A Cover On The Skillet, And Cook Another 10 Minutes. Serve Over The Cooked Rice.