Preheat the oven to 375 degrees F. Rub the potatoes' skins with the olive oil and transfer them to a baking sheet. Place the potatoes in the oven to roast for 30 to 35 minutes, until they're tender when poked with a fork. Remove the potatoes from the oven and set aside to cool.
Reduce the oven's temperature to 300 degrees F. Using a very sharp knife, slice the potatoes in half. If the potatoes are particularly small, you may need to slice about 1/4 off the tops. Next, carefully scoop the potato flesh into a mixing bowl, leaving a rim of potato in the shell to ensure sturdiness. To the bowl filled with the potato flesh, add the diced bacon, butter, sour cream, cheddar cheese, whole milk, jalapeño, salt and pepper.
Place heaping dollops of the cheesy potato mixture into each halved potato shell. Top each mound with a pinch of cheese. Repeat until all of the shells are filled with the potato mixture. Transfer to the oven to bake just until warm and the cheese has melted, about 10 to 15 minutes.
Garnish the bacon potato bites with a sprinkling of green onion. Serve immediately.
You may find it helpful to use a knife and run it around the edge and use a 1/4 teaspoon to scoop out the potato. Depending on your potatoes, you may need to slice a teeny bit on the bottom half so the potato can stand upright.