Preheat oven to 375 degrees. Place potato in a medium saucepan; cover with water. Bring to a boil; cook 4 minutes or until almost tender. Drain. Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan, reserving 2 tsp. drippings in pan. Crumble bacon; set aside. Add potato, onion, 1/4 tsp. salt, and thyme to drippings in pan; cook 8 minutes or until potato is lightly brown over medium-high heat. Remove from heat; cool. Combine the potato mixture, bacon, remaining 3/4 tsp. salt, 2 tbsp. chives, cheese, pepper, egg whites, and eggs, stirring well with a whisk. Coat 36 mini muffin cups with cooking spray. Spoon about 1 tbsp. egg mixture into each muffin cup. Bake at 375 degrees for 16 minutes or until lightly brown. Cool 5 minutes on a wire rack. Remove omelets from muffin cups. Top each with 1/2 tsp. sour cream and 1/2 tsp. chives.