A year ago, Nilsson faced the ultimate conflict between club and country. Sweden required him to captain them on the Wednesday against Austria, a match vital to their prospects of reaching the United States. Sheffield Wednesday wanted him 24 hours later to turn out against Arsenal in the FA Cup final replay. In the end he played for both, but paid a harsh price for his patriotism and professionalism.
'It took me five days to recover,' Nilsson recalled in an accent with unmistakable South Yorkshire inflections. 'I was totally drained and became quite poorly. I even had problems eating. I wouldn't do it again, but then it was a World Cup game and a Wembley final.'
Although Wednesday lost, conceding the winner minutes after their exhausted right-back was substituted deep in extra time, Sweden won 1-0. They eventually qualified for their ninth appearance in the finals, leaving Nilsson determined to purge the memory of their 1990 blow-out in Italy.
'I didn't enjoy the last World Cup,' he said. 'We had high ambitions but didn't do ourselves justice. We played like individuals, not as a team. This time it will be different. We seemed to be satisfied with an honourable defeat in our opening game against Brazil. I don't think that helped us prepare properly for the next one, against Scotland, and we had Jonas Thern, Glenn Hysen and Mats Magnusson struggling with injuries. Maybe we shouldn't have played all three, because we lost to the Scots and to Costa Rica as well.'
The latter pair, along with Johnny Ekstrom and Glenn Stromberg, are gone. They will be hard to replace, but Nilsson points to the number of Swedes playing in Europe as proof of the quality and adaptability of their squad. He also finds reassurance in the tactical continuity provided by Tommy Svensson's managership.
'Our players earn their livings in very different football cultures such as France, Portugal and England. But when we all come back together to play for Sweden, we have a pattern that we click back into. In some countries where our guys play, no one plays 4-4-2. We've tried five and three at the back but neither worked for us. As soon as we reverted to our system, things began to happen again.'
Tomas Brolin, the deep-lying striker who emerged as if from nowhere four years ago and has since established himself in Italy with Parma, will be expected to provide the unexpected. Nilsson has high hopes that Jesper Blomqvist, a pacy left-winger from IFK Gothenburg, and Henrik Larsson, who has exported his blond dreadlocks and finishing skills to Feyenoord, will make a similar breakthrough this time.
The draw did Sweden few favours, putting them in Group B with Brazil, Russia and Cameroon, as well as forcing them to flit between the time zones and temperatures of California and Michigan. Nilsson anticipates variable playing surfaces, too.
He confesses to knowing little about Cameroon, Sunday's opening opponents in Los Angeles, but trusts Sweden will have something to build on by the time they renew an old rivalry with the Brazilians. 'We've got to impose our own game. I feel we're the underdogs of our group,' he said.
At 30, this may be his last major tournament, although one club- mate, Mark Bright, is convinced Nilsson's fitness regime will enable him to go 'until he's 40'. Sadly for Hillsborough devotees, family reasons mean he will play next season for his home-town team, Helsingborg.
The Premiership has lost an unusual combination of composure and dynamism; a player unlikely to be celebrated in a fanzine title or T-shirt, but who, like Stefan Edberg, is blessed with a phlegmatic manner that is often mistaken for blandness.
Nilsson is relieved to have escaped Ryan Giggs, saddened at leaving behind 'the noise and humour' of English crowds, yet glad he no longer has to play so many high-pressure matches. 'You can't have such a congested programme and a good national side,' he said. 'The good teams do well in the cups and play piles of extra games. Suddenly they're off with England, playing with knocks that haven't cleared up.'
Which is where we came in. Nilsson has earned his World Cup swan song, though no one should be surprised if he resurfaces four years from now.