Looking for an Authentic Bavarian or Swiss City in between Zurich + Nordlingen

If you would consider Tyrolean rather than Bavarian, Innsbruck may be an option. Supposed to be a very scenic train ride from Zurich to Innsbruck: Arlsberg line. Innsbruck is also easily on train route(s) north to Munich, Garmisch-Partenkirchen, Nuremberg, etc.

Füssen. Neuschwanstein in Füssen was Walt Disney’s actual inspiration for Sleeping Beauty's castle in Disneyland.

Hike or take a carriage up to Neuschwanstein castle, explore Hohenschwangau castle a 15 minute walk away, wander the old town.

Late November is perfect timing: magical without peak season crowds. My most recent visit was on a Rick Steves My Way Alpine Europe tour. We stayed at the Zum Hechten Altstadthotel in the old town. A lovely hotel and only a 6 minute walk from the train station.

We are looking for somewhere to stay for a few nights that is located
in between Zurich and Nordlingen— evenly splitting the travel time.

Assuming that "between" should not involve adding lengthy detours, I would disqualify Innsbruck and Füssen, which would require 8-9`total hours or more. More direct train routes will entail 5+ hours. The journeys below split your time well and include a stopover in one of Germany's most charming old-world towns - Esslingen, which in late November offers a Christmas market as well. Sample travel schedules below...

8:37 - 11:51: Zürich > Esslingen
9:05 - 12:13 Esslingen > Nördlingen

Esslingen information...

https://www.esslingen-info.com/en

https://landlopers.com/2015/05/31/esslingen

Staying in Esslingen would allow you to make an optional day trip to another fine place called Tübingen, roughly 45 minutes Esslingen by direct train. Tübingen information...

https://www.tuebingen-info.de/_Resources/Persistent/5b64fd3ecc0c244207d301b60db28ba0e33a1a4a/Tour_of_the_city_2022.pdf

https://historicgermany.com/tuebingen/

Lindau might be an option for a stopover from Zürich to Nördlingen

Train Zurich to Munich stops there and there is a direct connection from Munich to Nördlingen

Only change trains once in Munich

See bahn.de

Zurich -Lindau 1,5 hrs by train
Lindau-Munich 2 hrs by train
Munich -Nördlingen 2hrs by train

Train stops in Lindau Reutin get a local train to Lindau Insel (4 minutes)
For Hotels and restaurants and historic center

The Romantic Road is wonderful, and Nordlingen is on the road.

https://www.romanticroadgermany.com
Also, on the road are Augsburg, Dinkelsbuhl and Donauwörth which are great.
Augsburg is over 2000 years old and worth half a day.

update You are all so generous to provide excellent recommendations! Thank you.

We have decided to give Füssen a try since it is so close to the Neuschwanstein castle (which was a non-negotiable on our itinerary), and there seems to be much to do there!

Just saying... 4. - 6. Dezember und vom 11. - 13. Dezember 2026 if you are flexible with your travel schedule.
https://www.fuessen.de/kultur/veranstaltungen/adventsmarkt/