Place the chicken breasts in the bottom of the crockpot. Scatter chopped onion over top. Spoon cream soup over top of that. Cover and cook on low for 7-8 hours or on high for 3-4 hours.
Note about chopping the chicken: A lot of folks have asked if or when they need to chop the chicken so the dish appears as it does in the photo. The great thing about this recipe is that by the time you add the rice, the chicken is so tender from being slow-cooked that stirring in the rice will cause it to break up and become shredded chicken as pictured. Hope you enjoy it!