* Nancy Lancaster, 96, an American-born socialite who had been an international influence on interior and garden design since the 1920s, died on Friday at her home near Little Haseley, Oxfordshire, England. A native of Virginia who moved to England in 1926, she helped create what is popularly known as the English-country look. This school of interior decoration is characterized by sun-bleached chintz, vibrant wall colors, a casual mix of furniture from various historical periods and an atmosphere of disheveled coziness.