To say it in a more formal way with fully proper grammar you would have to change the prefix to include the object nuq. Also, the -pu' makes it perfective, which is fine, but I'm going to go with the simple past. So the question would be nuq Dajatlh? However, nuqjatlh is listed in the Addendum of The Klingon Dictionary as an exclamation meaning, "What did you say?" Since we have not yet taught the grammar for the sentence nuq Dajatlh?, we teach this exclamation near the start.
I'm definitely hearing nuqjatlh. The j and the ch are very similar and officially the only difference is that the j is voiced and the ch is not, so it's an easy confusion to have, even for experience speakers. You should be able to distinguish the tlh from the H a little easier by listening for the stop of the vowel a for just a moment on the tlh which shouldn't happen with the H.