1 night in Dresden and 2 nights in Nuremburg?

The restored area of Dresden is quite small, so the main reason to visit the city, in my view, is the museums. You could spend a lot of time in them, if they happen to align with your interests, or comparatively little if you're sort of checking off the boxes. I'd suggest reading about the Dresden museums to determine how much they'll appeal to you. Personally, I loved the incredible treasures in the Historic Green Vault (timed ticket required) and spent at least 90 minutes in there alone. The (separate) Green Vault is also worthwhile. The other museums are larger; one has a lot of medieval armor, just as an example of what you'll find. I also took an interesting walking tour in Dresden, booked through the tourist office, that helped provide some historical background.

I haven't been to Nuremburg, so I can't compare.

Make sure you check the websites for the museums you want to visit, as traditionally they are often closed on Mondays in Germany.

Throw a dice. Both locations have enough sights for more than two days. I advocate Dresden because it's one of the lesser-known destinations.

Take either the historic cable car or the historic overhead railway on one of the surrounding hills to get a nice view over Dresden. Go to the Fürstenzug and see the 100 metres long picture of the Wettin family made from Meissen porcelain. See the Zwinger, Semper opera, Cathedral, Frauenkirche and the statue of August dem Starken. The Residenzschloss with its museums was already mentonied. You can eat on top of the historic Yenizde tobacco factory.

And you should visit the Elbsandsteingebirge southeast of Dresden and the Bastei formation, it's accessible by local bus, about a 1 hour ride. Or you can go on a steamboat ride up the Elbe river to reach it.

In the past, I have spent longer in Dresden than in Nuremburg. I guess museums are my thing. Whichever towns you stay in, you can also moderate your visit time by taking trains early or late in the day.