Preheat the oven to 400 degrees F (200 degrees C). Grease a 9x13-inch baking dish.
Prick potatoes with a fork. Place on a baking sheet.
Bake in the preheated oven until potatoes are easily pierced with a fork, 45 minutes to 1 hour.
Reduce oven temperature to 375 degrees F (190 degrees C). Remove potatoes from the oven and let cool completely, at least 30 minutes.
Cut potatoes into 1-inch cubes. Combine sour cream, Monterey Jack cheese, Cheddar cheese, bacon, green onions, salt, and pepper in a large bowl. Add potatoes. Spoon mixture into the prepared pan.
Bake in the preheated oven until cheese is melted, about 40 minutes.
