Ezekiel Bala's double gave Nigeria a deserved victory as Scotland slumped to consecutive defeats at the Under-20 World Cup finals in Canada.
Nigeria were worthy winners against Scotland in Canada
Nigeria goalkeeper Olufemi Thomas did well to thwart Ross Campbell early on.
But it was Scotland's Andrew McNeil who was the busier number one with a couple of fine saves to deny Brown Ideye.
And Bala fired through McNeil's legs after the break and headed in the second before Efe Ambrose was sent off for a tackle on Scotland's Ryan Conroy.
Nigeria will now qualify for the last 16 along with Japan from Group F, leaving Scotland needing a win in their final game against Costa Rica to have a chance of progressing.
Scotland manager Archie Gemmill had made sweeping changes.
But McNeil retained his place despite being at fault for two of the goals in the opening 3-1 defeat by Japan.
Andrew Cave-Brown, Graham Dorrans, Alan Lowing and Ryan Conroy were all dropped.
Ryan O'Leary, Andrew Considine, Robert Snodgrass and Campbell were the players replacing them.
Indeed, only four players, including McNeil, retained the same position as they did against Japan.
However, the reorganised Scots created the first chance.
The ball broke to Campbell inside the box, but Thomas turned wide the striker's effort from a difficult angle.
McNeil once more looked uncertain with his clearances as Nigeria started to dominate possession, but the goalkeeper redeemed himself with a superb save.
Ideye, who scored the only goal of Nigeria's opening win over Costa Rica, was found unmarked 10 yards out only for McNeil to claw the striker's header wide.
Campbell again found space behind the left back but screwed his shot wide of the far post from 16 yards.
A couple of loose passes allowed Ideye and Blessing Okardi to test McNeil again from long range.
He survived those, but Nigeria broke the deadlock three minutes after the break when Kevin Cuthbert failed to clear and Bala drove the ball powerfully through the keeper's legs from 16 yards.
Bala and Ewa Echiejile both fired into the side-netting as Nigeria took control.
But Scotland squandered a great chance when a Cuthbert cross was headed over the crossbar by Adams when Snodgrass was in a better position to score.
It was 2-0 after 78 minutes when McNeil could only parry a Akeem Latifu effort and Bala scored on the rebound.
Scotland at last applied some pressure once Nigeria were reduced to 10 men a few minutes later.
Thomas twice denied Lee Wallace from close range, while substitute Dorrans hooked wide.
And the African side held out for their second win of the tournament.