Just a heads up on Nuremberg to Prague. There are 2 ways, the easiest and fastest is a regional train to Schwandorf connecting to a regional train to Prague. Regional trains do not have seat reservations.
The other way is to Pegnitz, then a regional train to Cheb, CK, then an Czech IC train to Prague. Only the Czech IC train has seat reservations. Nuremberg to Pegnitz is by replacement bus as the rail line has several bridges that failed inspection and need repaired and this closure is indeterminate, at least as far as the current schedule to Dec 14.
Edit: You apparently can purchase seat reservations for Schwandorf to Prague from Ceske Drahy, the Czech rail company who jointly operate this train with Die Laenderbahn. Available from 30 days prior to departure and you can pick seats from a seat map.
https://www.cd.cz/en/
Cost for 2 is 149 CZK. As long as you are going to that site, you will also get a better price for the tickets for that train.