Grate carrots, zucchini and onions using large holes of box grater; place vegetables on center of large clean kitchen towel. Bring up ends of towel and twist together to form pouch. Holding pouch over sink, squeeze out excess moisture from vegetables. Place vegetables in large bowl. Add eggs, flour and pepper; mix well.
Heat oil in medium nonstick skillet on medium-high heat. For each latke, carefully add 1 Tbsp. of the vegetable mixture to skillet, cooking 2 to 3 latkes at a time. Immediately spread each mound into thin circle with back of spoon. Cook 3 to 4 min. on each side or until golden brown on both sides. Drain on paper towels. Repeat with remaining vegetable mixture.
Serve topped with sour cream. Sprinkle with chives.