In a large slow cooker, add the potatoes. Pour the chicken broth over and stir. Add minced garlic, chives, a little salt and 1/2 tsp. pepper. Add the diced onion and stir together well. Slice the butter and set it on top of the potatoes/broth.
Cook on high for about 4 hours or low for 6 to 8 hours.
About one hour before you're ready to eat, whisk together flour, heavy cream and milk in a bowl, so no lumps remain. Pour that into the slow cooker. Add 3/4 c. sour cream, 1 1/2 c. shredded cheddar, 1 Tbsp. reserved bacon grease, and 4 pieces of cooked bacon that have been crumbled. Stir that all together well, add salt to taste, then replace the lid and allow it to cook and thicken until completely heated through. About an hour.
Serve, topped with shredded cheddar, sour cream, diced green onions and the additional crumbled bacon.