The Barcelona star has struggled to make his mark on the tournament in Russia, with the Albiceleste facing elimination from the group stages.
A win for the Super Eagles, though, will ensure their passage into the knockout rounds, and though Leicester City forward Iheanacho is a fan of the five-time Ballon d'Or winner, he will be happy if Messi again fails to make an impact.
"I like Messi but against us I hope he stays quiet," he told Goal.
"It's going to be a boost for us to play against a big team. The win today will give us confidence to go against them."
Nigeria kept their hopes of reaching the last 16 alive after two goals from Ahmed Musa proved to be enough to beat Iceland in Volgograd.
They did not have things all their own way, however, with Gernot Rohr's side failing to record a shot on goal in the first half.
And Iheanacho, who was recalled to the side alongside Musa as the Super Eagles switched to a 3-5-2 formation, believes the team needed time to adapt to the change in system.
"There was a bit of confusion and we didn't get it right in the first half," he said. "It was much better after the break and we came out strong to fight until the end to get the result.
"We're happy with the result. It was a fantastic result for us heading into the next game."