We will be taking a river cruise from Budapest to Nuremberg in May, and were looking at extending the trip for a few days before heading back to the US. Brussels, Bruges? Or perhaps go to Lake Como?
Prague is a frequent extension on that cruise, and I suggest you arrive a few days early in Budapest. No stay, there, is long enough.
There are a multitude of choices available.
You didn't provide background information on where you had previously traveled in Europe.
Also, other than Brussels, Bruges or Lake Como where would you like to go?
I suggest trying to stick to places more geographically close to Nuremburg. Have you been to Prague, Berlin, or done the Romantic Road in Germany from Wurzburg to Garmisch?
Brussels is fine, but it didn't knock my socks off, although the Grand Plaze is impressive. Bruges is special, but why not pick somewhere closer.
I would spend a couple of days in Nubemberg, unless your river cruise does time there.
Prague would be toward a rather short drive or train ride away. Also, head on to Berlin or back to so the Romantic Road for 3-4 days.
You could fly out of Berlin if you went in that direction, or Munich if you did the other.
Nuremberg itself is a great place. It's also a good base for day trips by train...
Bamberg is a UNESCO World Heritage city and just 45 minutes away by direct train. Two people pay €20 round trip on a VGN day pass (buy at ticket machine.)
We did the 3 days in Prague after that cruise and loved it. I wish we had arrived in Budapest so we could have spent more time there. Back to your question, Bruges over Brussels every time. Or perhaps Paris if you haven’t been there. I haven’t been to Lake Como, so I can’t comment on it.