This easy slow cooker orange chicken recipe served with rice is the best weeknight dinner. tender chicken breast pieces are covered in sweet and sour sauce. i have been tweaking this slow cooker orange chicken recipe for about 6 months. to be honest, i was having a really hard time finding the perfect orange flavor. i made slow cooker orange chicken with mandarin oranges and even a crockpot orange chicken with orange juice. both were mediocre and didn't blow me away. however, after making this easy crockpot orange chicken recipe with orange marmalade, i knew i had a winning recipe. you don't have to.