Learn Dutch: Niemand praat tijdens het concert. - Nobody talks during the concert.

Yes! Tijdens is a preposition of time meaning 'during.' Just like in English, it is followed directly by a noun or noun phrase, which in this case is het concert.

Why does niemand take the singular verb form praat?

Even though it represents zero people, niemand (nobody) is always treated as a singular pronoun in Dutch. Therefore, you use the singular verb form praat, exactly like how you say 'nobody talks' in English.

If I want to emphasize the time and start with Tijdens het concert, how does the sentence change?

Moving Tijdens het concert to the first position triggers inversion because of the Dutch V2 (verb-second) rule. The verb must remain in the second slot, so the subject niemand moves directly after it: Tijdens het concert praat niemand.