Making their sixth appearance in the showpiece competition, Nigeria are bringing their most inexperienced squad ever to Russia next year.
"This is a difficult group, but I think we can spring a surprise."
Nigeria clawed their way back from a 2-0 deficit to claim a stunning friendly win over Argentina at the Krasnodar Stadium in Russia on November 14.
Argentina did not have superstar Lionel Messi last month.
"But we also played without Victor Moses," Rohr said in reference to the talented Chelsea winger.
Nigeria have shown much promise since making their World Cup debut at the 1994 competition in the United States.
They fought hard before falling to Argentina 2-1 in their debut finals, winning plaudits for bringing sub-Saharan African flare to the game.
Their 1994 bow may also have been their most memorable, ending in a 2-1 extra-time last-16 defeat by Roberto Baggio's Italy, who went on to lose the final to Brazil on penalties.
Nigeria have never reached the quarter-finals and lost 3-2 to Argentina in the 2014 World Cup in Brazil, when they were beaten by France in the last 16.
Rohr said their toughest match will be against Croatia on June 16 in Kaliningrad, because it will be Nigeria's opener.
"The first game is always the most difficult," he added.
He also attributed Nigeria's failure to fully fulfil the promise others saw in them to a lack of discipline that he intended to fix.
"I believe that African players have the talent, they have the physical and technical possibilities, but what they are missing is organisation, what they are missing is discipline," said Rohr, who has also coached Gabon, Niger and Burkina Faso.