Preheat the oven to 400 degrees F. Place the potatoes on a large rimmed baking sheet and drizzle with oil. Rub the potatoes with oil on all sides, then sprinkle liberally with salt. Bake for approximately 1 hour, until crispy on the outside, but tender on the inside.
Cut the top third off each potato. Peel the skin off the top and place the potato flesh in a mixing bowl. Then use a spoon to scoop most of the potato flesh out of each potato, leaving only enough to keep the sides stabilized.
Use an electric mixer to beat the potato flesh with the sour cream and milk. Add the shredded cheese and taste. Salt and pepper if needed. (The potato mixture might seem a little sticky or gloppy, but don't worry. It fluffs up in the oven.)
Spoon the potato filling back into the empty potato skins. Then sprinkle the top of each potato with crumbled bacon and bbq potato chips. Bake for 15-20 minutes, until puffy and golden.
Serve the twice baked potatoes warm, garnished with chopped green onions.