Preheat the oven to 425°.
Using a fork, prick the potatoes.
Bake for 40 to 50 minutes or until tender.
Cut the potatoes lengthwise into quarters.
Scoop out the pulp with a small spoon, leaving 1/4"-thick shells.(Set the pulp aside for another use.)
Spray a cookie sheet with no-stick spray.
Place the potato shells on the sheet with the skin sides down.
Spray the potatoes with the no-stick spray.
Bake at 425° for 10 to 15 minutes or until crisp.
Sprinkle the Monterey Jack cheese and cheddar cheese on the potatoes, then bake about 2 minutes more or until the cheeses are melted.
Sprinkle with the green onions or chives and serve.