He will join in May to replace Paul McDowell, who announced in September that he would leave Nacro in February to become HM Chief Inspector of Probation.
Tas, who joined Action for Children three years ago as executive director of operations, has also been director for England at the Prince’s Trust.
He has been acting head of Action for Children since Dame Clare Tickell left in December to become chief executive of the housing association Hanover.
Graham Beech, director of strategic development at Nacro, will act as its interim head until Tas begins as chief executive.
Tas will continue to serve on the board of Dutch Pension Fund and as a trustee for the children’s charity War Child.
He has been a volunteer with Amnesty International in Taiwan, the Netherlands and the UK. He was also human resources manager at the shipping company P&O Nedlloyd.
"Nacro does amazing work changing lives and reducing crime," said Tas. "I am very much looking forward to commencing my role and working with the staff, trustees and leadership team to deliver positive and real outcomes for individuals and communities across the board."
Matthew Litobarski, chair of Nacro, said of Tas: "His skills and experience, together with his enthusiasm for the role, combined to make him an outstanding candidate for us. We are very much looking forward to him joining us."