Preheat oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish.
In a large bowl, toss diced potatoes with olive oil, paprika, garlic powder, onion powder, salt, and black pepper until evenly coated.
Spread the potatoes evenly in the prepared baking dish. Bake for 25 minutes, stirring halfway through, until potatoes are just starting to soften.
Remove the dish from the oven and add cubed chicken on top of the potatoes. Sprinkle with half the cheese and half the bacon.
Return to oven and bake for another 20-25 minutes, until chicken is fully cooked and potatoes are tender.
Remove from oven and sprinkle with remaining cheese and bacon. Bake for an additional 5 minutes, until cheese is melted and bubbly.
Top with chopped green onions and serve warm with ranch dressing on the side if desired.