When the chicken is done, shred it right in the slow cooker using two forks. Stir in the sour cream, half of the cheddar, and about two-thirds of the crumbled bacon until smooth and creamy. Taste and season with a little more salt and pepper if needed. Keep warm.
Let the baked potatoes rest for 5 minutes so they’re easier to handle. Split each one lengthwise and gently fluff the insides with a fork. If using, dot with the butter and a pinch of the remaining kosher salt and pepper.
Spoon the warm chicken mixture into the potatoes, mounding it high. Top with the remaining cheddar and the reserved bacon. Broil on the upper rack for 2 to 3 minutes, just until the cheese melts and the edges take on a little color. Watch closely.
Drizzle with ranch dressing and finish with green onions and chives. Add diced pickled jalapeños if you like a little kick. Serve hot.
Shortcut option: Microwave scrubbed, oiled potatoes for 8 to 10 minutes, turning halfway, then transfer to a 425°F oven for 20 to 25 minutes to crisp the skins before stuffing.