His appointment is one of a raft at senior level which also sees Booths supermarkets executive chairman Edwin Booth become the group's chairman, replacing Dudley Ramsden.
The deputy chairman's position ha d been vacant since last October.
Neil Turton, who has worked for Nisa-Today's for 16 years, most recently as chief operating officer, becomes chief executive in a newly-created role.
The appointments are said to mark Nisa-Today's commitment to reshaping its senior leadership in the wake of failed merger negotiations with Costcutter .
"The company hopes this new structure with greater member involvement reflecting the diversity of the group will provide a platform for future growth," a spokesman said.
Booth, who has been Nisa-Today's deputy chairman for six years, said: "After the difficulties Nisa-Today's experienced last year, I am encouraged that the board displays a hunger to do business and drive value for the benefit of both retail and wholesale members."
Chatha has been a member of Nisa-Today's since 1987 and has sat on the board for three years.
Turton said: "My plan is to work with the board and staff to develop Nisa-Today's as an organisation to be proud of, embedding best corporate governance practices and combining these with Nisa-Today's trading acumen."