First, preheat your oven to 425°F and line a large baking sheet with parchment paper. In a small bowl, whisk together the buffalo sauce, olive oil, ranch seasoning, and black pepper. Next, place your diced potatoes in a large bowl and pour half of this buffalo mixture over them, tossing well to ensure every piece is evenly coated.
Spread the coated potatoes in a single, even layer on the prepared baking sheet. Roasting them in a single layer is crucial for achieving that desired crispiness. Bake for 60-70 minutes, flipping them about halfway through, until they are golden brown and crispy on the outside.
While your potatoes are in the oven, it’s time to get the chicken ready. Place the bite-sized chicken pieces into a resealable plastic bag. Pour the remaining half of the buffalo mixture over the chicken, seal the bag, and give it a good shake to coat the chicken completely. Let it marinate in the refrigerator for at least 30 minutes.
Once the potatoes are perfectly roasted, spray a 9x13-inch baking dish with cooking spray. Transfer the hot, crispy potatoes to the dish and spread them out. Top the potatoes with the marinated chicken. Bake for 18-20 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F.
Remove the dish from the oven. Sprinkle the shredded cheddar cheese, Monterey Jack cheese, and crumbled bacon evenly over the chicken and potatoes. Return the dish to the oven for another 5-10 minutes, just until the cheese is melted, bubbly, and slightly golden. Let it rest for a few minutes before serving.