Nestor George Chylak Jr. (; May 11, 1922February 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 worked home plate in the decisive Game 7) and 1977. He also worked in six All-Star Games: 1957, 1960 (both games), 1964, 1973 and 1978, working home plate in the second 1960 game and in 1973.