Prepare rice according to package directions; set aside. Heat oil in large Dutch oven over medium-high heat. Add chopped onion and next 4 ingredients (through mushrooms) and sauté 6 minutes or until onion is tender. Spoon flour lightly into dry measuring cup and level with a knife. Stir flour, tarragon and thyme into onion mixture and cook 1 minute, stirring frequently. Add 2 cups water, sherry, broth and evaporated milk; bring mixture to boil.. Reduce head and simmer 20 minutes or until slightly thick. Stir in cooked rice and chicken; cook 10 minutes or until thoroughly heated. Serves 8