Nanni's grandparents immigrated to the United States from Collebrincioni, Italy. He grew up in South Bend, Indiana and earned a bachelor of arts, majoring in theology and computer applications at the University of Notre Dame in 1988, while playing as a walk-on for the Fighting Irish basketball team.
After college Nanni spent a year as a Holy Cross Associate volunteering as a counselor for the De Paul Treatment Center in Portland, Oregon and the next year as a professional addiction counselor at Great Oaks Village in Orlando, Florida. While in Florida he spent three years on the parish council for Dominican Republic Missions in the Diocese of Orlando. In July 1993 he began working as executive director of a youth center, La Casa de Amistad, in South Bend. Four years later he was named principal of Cristo Rey Jesuit High School in Chicago, where he spent seven years. While there he completed a master's in theology and research at the Catholic Theological Union in Chicago, Illinois in 2000 and a master of arts/master of social work in social-service administration at the University of Chicago in 2002.
In 2004 Nanni returned to South Bend as vice president of programs for the Community Foundation of St Joseph County. After nine years there he was hired to succeed Kate Nielsen as president and CEO of the Community Foundation of Greater Birmingham.
Nanni and his wife, Allison, have three children. Nanni's older brother, Louis, is vice president of university relations for the University of Notre Dame.
- Carbone, Matt (January 19, 1994) "An Inside Look: Holy Cross Associates serve, learn in nation's larger cities" The Observer
- Tomberlin, Michael (March 31, 2014) "Meet Chris Nanni, the new CEO of the Community Foundation of Greater Birmingham." The Birmingham News
- Johnson, Roy S. (November 15, 2019) "Inspired by life journey of inclusion, ‘we’ve got to be honest’ about race, says foundation CEO." The Birmingham News