Take the bus operated by Deutsch Bahn www.dbahn.de There is direct service from the Nuremburg main train station to the Prague main train station. It takes a few hours for the journey and you can get tickets for as low as 19 euro if you book ahead and get the Saver Fares.
If you go to dbahn.de it will provide train schedules for all of europe - although you will have to buy tickets at the train station in Prague.
You can avoid the bus, if you'd prefer a train, as I certainly would.
Book Nuremberg to Prague from €19 at www.cd.cz/eshop
There are several services a day with 1 simple change at Schwandorf, see http://www.seat61.com/munich-to-prague-by-train.htm
Book Nuremberg to Prague from €19 at www.cd.cz/eshop
There are several services a day with 1 simple change at Schwandorf, see http://www.seat61.com/munich-to-prague-by-train.htm