Place potatoes in a large pan, cover with cold water, and bring to a boil over high heat. Reduce heat; simmer uncovered until tender, about 15-20 minutes. Drain potatoes, return to pan. Heat the potatoes on medium until they are dry, about 2 minutes, stirring occasionally. Add milk. Using a potato masher, mash the potatoes until fairly smooth. Remove from heat, stir in chives, salt and pepper. Place in covered container and chill until cold. Form potato mixture into 12 patties-about 3 ½ inches round and ½ inch thick. Melt 1 tsp. butter to skillet and cook 3-4 of the patties until golden brown. Repeat with others. Keep the patties warm in a low, 200°F oven, while cooking the others. Serve warm with sour cream.