Victor Moses scored twice and Chelsea teammate John Obi Mikel once as Nigeria crushed Liberia 6-1 in Calabar to advance after the first leg finished 2-2 in Monrovia last month.
Efe Ambrose, Ahmed Musa and Ikechukwu Uche were also on target for the Super Eagles, who have suffered numerous Cup of Nations disappointments since last lifting the trophy 18 years ago.
Nigeria were favoured to progress, but the winning margin over the Lone Stars exceeded expectations and will cheer coach Stephen Keshi, who promised to quit if his team failed to reach South Africa.
Early on Saturday, defending champions Zambia qualified for the 2013 Africa Cup of Nations Saturday after winning a marathon penalty shootout in Uganda.
Ghana also became the first team to qualify for the finals with an early Afriyie Acquah goal giving them a 1-0 win over Malawi in Lilongwe having taken a two-goal advantage to the Civo Stadium.
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