Nestor George Chylak, Jr. (/ˈtʃaɪlæk/; May 11, 1922 – February 17, 1982) was an American umpire in Major League Baseball who worked in the American League from 1954 to 1978. He umpired in three ALCS (1969, 1972, 1973), serving as crew chief in 1969 and 1973. He also called five World Series (1957, 1960, 1966, 1971, 1977), serving as the crew chief in 1971 (in which he called balls and strikes in the decisive Game 7) and 1977.