Signage has gone up on the former Chicken Cottage site on Lavender Hill, close to Clapham Junction.
It will reopen as Nando's Nino on 29 October. Planning documents show the site will have an open kitchen with seats for around 17 dine-in customers.
Nando’s began trialling the Nino express format in Twickenham in January 2018 and a second site opened in Fulham earlier this year.
The concept offers a streamlined food menu and slightly wider range of craft beers and ciders.
Nando's also runs a full-service restaurant on Northcote Road, a short walk away from its new Clapham site. It may look to use the Nino's location to take pressure off the kitchen to meet delivery demand, as well as capturing footfall around Clapham Junction station.
Chains including Tortilla and Five Guys have similarly trialled smaller express-style sites over the past two years in the face of higher rents and rates on the high street.
Nando’s opened its first UK restaurant in Ealing in 1992 and now operates around 400 sites across the country.