In pan, simmer first 3 ingredients until soft, 10 minutes; in blender, puree with cilantro and 1/2 tsp.salt. Spread 1/2 cup in 9-by-13-inch baking dish. Divide chicken, beans and 1 cup cheese among tortillas. Roll; place in dish. Top with remaining sauce and cheese. Bake at 400° until bubbly, 20 minutes.