Esther Nieto Machuca, a national organizer for women in the League of United Latin American Citizens, was born on October 10, 1895, in Ojinaga, Chihuahua, Mexico, to Juan and Carolina (Rodríguez) Nieto. Her father was a lawyer and civil engineer. She married Juan C. Machuca on June 26, 1915, and they had one son. She and her husband had prominent national roles in LULAC. Around May 1934 Esther Machuca acted as a charter member and first treasurer of the ninth women's chapter of LULAC, in El Paso, called Ladies LULAC. She and other members of council nine decided to disband in 1936 because several national officers, all men, ignored their council. In 1937 she helped reorganize Ladies LULAC Nine, and she helped establish council fifteen in Laredo. In June 1938 she served as the official hostess for the LULAC national convention in El Paso. There she was in charge of entertaining women delegates and visitors at social functions. After LULAC president general Filemon T. Martínez took office at that convention, he appointed Esther Machuca ladies' organizer general. This office first existed in 1934–35, but it was Mrs. Machuca's tenure in that office in 1938–39 that made Ladies LULAC a national entity. She helped establish Ladies LULAC chapters in Las Vegas, New Mexico, and in Dallas. When she left office, three or four women's chapters in California, Arizona, and Texas were organizing.
As a leader, she wanted LULAC women to sponsor an issue of the LULAC News, the official magazine of the league. Women sought out advertisements and wrote articles for one of the issues. The May 1939 edition, conceived, edited, and produced by Esther Machuca, is the only one ever produced by women in LULAC and one of only two issues about LULAC women. The magazine had photos, human interest stories, and information on officers, councils, history, and prominent members. It was also one of the thickest editions, with sixty-eight pages. It was dedicated to Antonietta Delgado de Martínez, Ladies LULAC member and deceased wife of Filemon T. Martínez.
In 1939 Esther Machuca devoted all of her extracurricular activities to LULAC. She was a member of council nine in 1975. Little is known of her work within the council, but it is the only Ladies LULAC council formed in the 1930s that still existed in the 1980s. She was also a member of La Tuna Ladies Auxiliary, Catholic Daughters of America, American Legion Ladies Auxiliary, St. Anthony's Altar Society, and St. Patrick's Catholic Church. She died on January 26, 1980, and is buried at Evergreen Cemetery in El Paso.