Nall, who was the only candidate to apply for the post as chair, will succeed outgoing chair Paul Breckell when he steps down in September.
"The CFDG has much to contribute as the foremost finance body operating in the sector and I look forward to working with our members and other stakeholders in delivering that contribution," Nall said.
Breckell, who is leaving the CFGD having fulfilled the maximum four-year term as chair, said he offered Nall his "full support" in taking the CFDG forward.
A spokeswoman for the CFDG said that Nall's strengths were his breadth of experience at senior management and governance levels in the Childrens' Society, charITyshare and the Charities Consortium.
"Charles is very well respected in the sector," she said. "He frequently writes and speaks on finance-related issues, such as money laundering and governance, and has done much to raise the profile of finance directors."
Nall is currently chair of CFDG's public affairs committee, and served on the umbrella body's policy development working group before becoming a trustee. In this capacity, he dealt with issues such as the sector's response to the Pension Protection Fund levy and to the European Union's proposals on money laundering and terrorism.