The family-run business has three stores ranging in size from 15,000sq ft to 20,000sq ft and the company is also finalising plans to open a number of new stores in the west of Ireland.
Pat Joyce, owner and managing director of Joyces 365, said: "The market in the Republic of Ireland is fiercely competitive. Nisa-Today's extensive product range and high-quality promotions will give us a point of
difference and send our customers a strong message of choice and value."
The news follows the appointment of a Nisa-Today's business development manager for the north and south of Ireland, areas in which it says it is keen to expand.
Nisa-Today's group sales director Andrew Mouse said: "We have been assessing the opportunities for extending our business and logistics model into Southern Ireland for some time, since it has significant similarities to the UK market."
Mouse added that the Irish market presented a strong opportunity for growth. Nisa-Today's is currently reviewing its supply chain operations and assessing whether to open a depot in Ireland.