Pour about half of the sauce mixture evenly over the layer of raw diced potatoes, gently stirring the potatoes just enough so they’re lightly coated but still in an even layer.
Lay the chicken breasts directly on top of the potatoes in a single layer, nestling them in but keeping them mostly on top so they cook evenly.
Pour the remaining sauce over the chicken breasts, spreading it with the back of a spoon so each piece is well coated and some sauce drips down over the potatoes.
Cover the slow cooker with the lid and cook on LOW for 5 to 6 hours, or on HIGH for 3 to 4 hours, until the chicken is cooked through (165°F in the thickest part) and the potatoes are tender.
Once cooked, taste the potatoes and sauce and add salt and pepper if needed (the ranch mix is salty, so season at the end). For a more shredded, casserole-style dish, use two forks to shred the chicken breasts directly in the slow cooker and stir everything together. For a more classic bake, leave the chicken breasts whole and spoon the creamy potatoes around them.
Let the chicken and potatoes sit in the warm slow cooker for about 5 minutes with the lid off to slightly thicken the sauce before serving. Serve hot straight from the slow cooker.
For a slightly richer version, swap half of the chicken broth for heavy cream or evaporated milk. If you like a little color and sweetness, scatter 1 to 1 1/2 cups of baby carrots or frozen mixed vegetables over the potatoes before adding the chicken. To lean more into that farmhouse flavor, sprinkle 1/2 teaspoon of smoked or sweet paprika over the chicken along with a pinch of black pepper before pouring on the sauce. If you prefer dark meat, boneless skinless chicken thighs work beautifully and stay extra juicy; just trim excess fat and cook on LOW for about 6 hours. For a lighter take, use reduced-sodium cream of chicken soup and low-sodium broth, then adjust seasoning at the end. You can also prep everything the night before: dice the potatoes and store them submerged in cold water in the fridge (to prevent browning), then in the morning drain them, add to the slow cooker, place the chicken on top, whisk the sauce, and start cooking before you head out the door.
