Second-half goals from Moses Simon and Efe Ambrose finally broke Swaziland's resistance and sent Nigeria through to the final group stage of the CAF section of World Cup qualifying with a 2-0 win.
Sunday Oliseh's team were held to a goalless draw in Friday's opening leg and they endured a similar story of first-half frustration in front of their own fans at Port Harcourt.
The unexpectedly dogged defence of a team ranked 130th in the world by Fifa was eventually broken six minutes after half-time when Simon curled home a magnificent 35-yard free-kick.
Nigeria had to wait until the 87th minute to make certain of their progress as Ambrose converted another set-play from close range, before Phumlani Dlamini's second yellow card meant the visitors concluded their unlikely World Cup bid with 10 men.
Swaziland spent the majority of the first leg on the back foot and, despite pre-match suggestions from their coach Harris Bulunga that they would take a more attacking approach, a familiar pattern developed during the opening stages at the Adokie Amiesiemaka Stadium.
Odion Ighalo sent a header narrowly over the crossbar and the Watford striker was at the forefront of an expansive start from Oliseh's men.
Simon scuffed Ahmed Musa's cross into the arms of Swaziland goalkeeper Nhlanhla Gwebu, before Ighalo swivelled to shoot agonisingly wide after half an hour.