The Super Eagles came back from two first half goals down to produce a brilliant second half performance, which involved three goals.
On resumption for the second half, Eagles up their game with skipper John Mikel Obi who was playing his 80th global game at the senior level for Nigeria spraying accurate passes.
Man of the match Iwobi drew Nigeria level in the 52nd minute after he combined well with strike partner Iheanacho.
Newly invited Brian Idowu made it 3-2 for Nigeria in the 54th minute of the game while Iwobi scored his second goal of the game to make it 4-2 and seal the victory for Nigeria.
Iwobi sealed the victory in 73rd minute when he smashed home from an Ahmed Musa pass to put more misery on Jorge Sampaoli's team.More news: GE cuts dividend for second time since Great Depression
Enyeama quit the team in 2015 after falling out with then head coach Sunday Oliseh but there have been loud calls for him to return for next year's World Cup.
The victory, earned at the Krasnodar Arena Stadium in Russian Federation, has bolstered the team's confidence as they kick off preparations for the 2018 FIFA World Cup.
"We also agreed on preparation, such as how much players will be paid for the friendly matches, including how and when the monies would be paid".
Referencing a previous heart problem, Argentinian team doctor Donato Villani told reporters: "He felt bad twice, and with the medical history he has, since he was operated on when he was 15, we wanted to be sure it was nothing".