To prepare Ancho Chile Sauce, remove and discard stems from chiles. Pour boiling water over chiles in medium bowl; let stand 30 minutes or until chiles are softened. Drain chiles, reserving liquid. Place chiles with seeds, 1/2 cup reserved liquid, sour cream, brown sugar, garlic, and salt in food processor bowl. Cover; process until smooth. Set aside.
To prepare Verde Sauce, place tomatillos in medium saucepan. Add enough water to cover. Bring to a boil; cook 8-10 minutes or until tender. Drain; coarsely chop tomatillos. Combine tomatillos, cilantro, onion, lime juice, jalapeño, garlic, oil, sugar, and salt in medium bowl. Set aside.
Heat oven to 350°F. Brown ground beef with onion in large non-stick skillet over medium heat 8 to 10 minutes or until beef is no longer pink, breaking beef up into 3/4-inch crumbles. Pour off drippings. Stir in 3/4 cup of the Verde Sauce, corn, salt, cumin, and black pepper; cook 2 to 3 minutes or until heated through. Stir in 1/2 cup cheese; remove from heat.
Reserve 1/3 cup Ancho Chile Sauce; pour remaining sauce into shallow dish. Spray 11 3/4 X 7 1/2-inch baking dish with nonstick cooking spray. For each enchilada, dip 1 tortilla into sauce to coat. Spoon about 1/2 cup beef mixture down center of tortilla. Fold 1 side of tortilla over filling and roll up. Place seam-side down in baking dish. Pour any remaining sauce from shallow dish over enchiladas.
Cover with aluminum foil. Bake in 350°F over 20 minutes. Remove foil; top with reserved Ancho Chile Sauce and remaining 1/4 cup cheese. Cover and bake about 5 minutes or until cheese is melted. Serve with remaining Verde Sauce.