Preheat your oven to 400°F (200°C).
Wash and chop the russet potatoes into bite-sized cubes.
In a large bowl, toss the cubed potatoes with olive oil, salt, and pepper until well coated.
Spread the seasoned potatoes evenly on a baking sheet and roast for 25-30 minutes or until golden brown.
While the potatoes are roasting, slice the smoked sausage into bite-sized pieces.
Heat a skillet over medium heat and add the sliced sausage, cooking until browned.
In a mixing bowl, combine the roasted potatoes, browned sausage, ranch seasoning, sour cream, and half of the shredded cheese.
Transfer the mixture into a greased baking dish.
Top with the remaining cheese and bake for an additional 15-20 minutes.
Remove from the oven and let it cool slightly before adding chopped green onions.
Serve warm and enjoy your loaded cheesy ranch potato bake!