Chason was previously operations manager for the north east. He replaces David Davidson, who oversaw the retailer's operations in both Northern Ireland and Scotland and will now focus solely on Scottish branches.
Sainsbury's holds a 14% market share in the province. The role has been created as part of the retailer's aim to grow space by 15% by 2011 in Great Britain and Northern Ireland.
In the past 18 months, Sainsbury's has opened stores in Dungannon, west Belfast and Carrickfergus. It plans to introduce a further three in Bangor, Derry and Dundonald and is also investing £5m in revamping its border store in Newry.
"Neil has a vast range of experience within the business and with 12 stores and several more in the pipeline this is a demanding, full-time role that requires the expertise and knowledge of a long-term Sainsbury's colleague," said a Sainsbury's spokeswoman.
"He will manage the region and feed back into the zone team. This includes supporting stores, the regional buying team and working with relevant colleagues to pursue new opportunities," she added.
Chason joined the company in 1981 and has held roles including deputy operations manager and loss prevention manager.