Train transfer

No, this is not to tight. The railway would not offer this otherwise. But you should not buy tickets that bind you to a train when arriving by air. Buy a flexible ticket, or buy your ticket when you arrive.

There are direct trains from the Airport to Nuremberg.

Thank you! I’ll try to book direct.

OP WengenK wasn't exactly suggesting that you book directly. He was pointing out that there were direct trains from the airport with no need for a transfer. These appear to be hourly, on the quarter hour. Given that there is no guarantee that your plane will arrive on time, consider downloading the app and booking the next train once you clear Passport Control or just buy at the station. This is a regional train. There's no cost benefit to advance purchase, and you can't reserve a specific seat.

Where is your flight coming from. Considering that it must be scheduled to arrive at MUC at about 13:38, I don't think it's coming from across the Atlantic (too late in the day, I think). You can never count on trans-Atlantic flights arriving on time. I've been an hour late arriving in Germany 3 out of 11 times since 2000.

If your flight is NOT coming from another Schengen country, you'll have to go through immigration, and that could easily take more than 13 minutes

I assume you know that ICE 504 goes non-stop from Munich Hbf to Nürnberg. You have to take an S-Bahn into the Hbf to catch it.

The direct train from MUC (airport) to Nürnberg is the RE22. One leaves every hour at 16 minutes past the hour. Since it's a regional train, any ticket for it, or a pass (Bayern-Ticket), will be good on any regional train(s) on that route that day, so missing it is not a worry. I suggest you plan on taking the RE22.

BTW, I've never bought tickets for a regional trains in advance. But if you do, as I said, they will be valid for any regional train that day, so if you miss the train you bought the ticket for, you can just get on the next one.

The RE22 uses the same airport station that the S-Bahn uses.