Les Bleus must overturn a two-goal deficit at the Parc des Princes if they are to reach the Brazil finals after losing the first play-off 2-0 in Kiev on Friday night, Roman Zozulya and Andriy Yarmolenko doing the damage for the hosts in the second half.
France, who risk missing out on a World Cup appearance for the first time since 1994, had plenty of chances to score with Nasri perhaps presented with the best opportunity when Franck Ribery put him through on the Ukraine goal.
The Manchester City midfielder took too long to pick his spot, however, allowing Andriy Pyatov to snaffle the ball in good time.
Nasri rejected suggestions he had been dithering in possession, instead claiming he had simply been looking for a better route to goal.
He told L'Equipe: "No, I did not hesitate. My first thought was to the cross the ball because I didn't think I could get past the keeper at his near post.
"I saw how he was positioned, and that the angle was open, but when I put my head down to concentrate on my footwork he closed me down.
"I have regrets because I think that I could just have hit it hard towards the near post, but if I'd missed there I would have looked ridiculous.
"I think I'll replay that moment 200,000 times in my head, hoping that I'll have another chance like that on Tuesday but that it goes straight in next time."
Ukraine broke the deadlock in the 61st minute as Edmar set up Zozulya from the centre of the area, the Dnipro Dnipropetrovsk striker slotting the ball past Hugo Lloris from 12 yards.
Arsenal defender Laurent Koscielny, who was later sent off, conceded a penalty for a foul on Zozulya and Yarmolenko stepped up to blast the penalty past Lloris.
"It is hard to take," Nasri added. "When you look at the game, the 2-0 win was not deserved because we had chances, me especially.
"We had bad luck with both goals because Hugo (Lloris) touched the ball on both occasions. Apart from that, we weren't really troubled."
Nasri has assured Ukraine they will endure an "aggressive" and uncompromising welcome to Paris when the soul-searching has finally finished in the France camp.
"It's going to be difficult but we still have the return leg at the Stade de France," he added.
"We will show our more aggressive side and we will do everything we can to overturn the deficit."