Mats Hummels set them on their way in the 23rd minute for a league record eighth win on the road from eight games in one season.
Robert Lewandowski added another goal two minutes from time as Dortmund notched their 13th win from 15 games to lift themselves to 40 points, surpassing the previous best mark at this stage in the season of 38 set by Bayern Munich in 2005/06.
Borussia had already secured top spot for the winter break before their game on Sunday after second-placed Mainz 05 lost 2-1 to Eintracht Frankfurt on Saturday. There are still two games left before the winter break.
Dortmund have twice before been top at the winter break - in the 1994/95 and 1995/96 seasons - and both times ended up winning the Bundesliga title.
"Obviously I can read the table but it is still only a successful season up until now. What we would like is to keep it going," said Dortmund coach Jurgen Klopp.
"I was surprised to hear that no team had won eight consecutive matches away (in one season). I have never had to deal with a title run in my life and percentages are not my strong point either," said Klopp, adding the season still had a long way to go.
HUMMELS LEAD
On a snowy and bitterly cold afternoon in Bavaria, Dortmund initially showed little of their offensive appetite that had produced an eye-popping 35 goals in 14 games until Sunday.
Lewandowski, replacing Dortmund's injured top scorer Lucas Barrios, had a shot on goal after a quarter of an hour but they had to wait until the strike by Hummels to take the lead.
Turkey international Nuri Sahin sailed a 40-metre free-kick from the halfway mark deep into the Nuremberg box and central defender Hummels scored with a well-taken diving header.
Undeterred by increasing snowfall, dominant Dortmund pushed forward as Nuremberg fell even further back and were rewarded when Lewandowski turned and fired from inside the box to seal victory.
Earlier on Sunday, Bayer Leverkusen struck twice in six second-half minutes to edge past visitors Cologne 3-2 and move within a point of second-placed Mainz 05.
They took the lead through Patrick Helmes before Cologne levelled six minutes later when Germany international Lukas Podolski curled a free kick into the box and Brazilian Geromel volleyed in.
The hosts took control when Tranquillo Barnetta and Stefan Reinartz netted in the second half with Cologne cutting the deficit through substitute Martin Lanig in the 65th minute.
Defeat left Cologne on 12 points, one place off the bottom.
On Saturday, Schalke 04 stunned Bayern Munich 2-0. The champions are in seventh place, 17 points off the top.
