Born in Parras. in the northern province of Coahuila, Cárdenas was a student of Polish language and literature as well as of cinema and the dramatic arts. After taking her doctorate at he National Autonomous University of Mexico, she studied at Yale and Lodz.

In the 1970s she won several accolades for her work as a stage-director. Cárdenas was ahead of her time in 1973 when she became the first person to speak out in defence of homosexual rights on Mexican television. In 1972, her production of Mart Crowley's Boys in the Band caused controversy. It was officially condemned as "immoral and offensive to good taste" but was brought to the stage following a campaign led by other intellectuals and writers.

In 1975, as a contribution to the International Year of Women, Cárdenas addressed a conference in Mexico City on lesbianism. As she left she was met with placards calling for the deportation of all "perverts and degenerates" from Mexico.

Cárdenas wrote that those who persist in seeing homosexuality as aberrant are fossils from another age. "To love like this, openly and without guilt," she writes, "is to live in the twenty-first century. Nancy died for cancer.