Sort of. Some of the letters make different sounds than they would in English, so pronuncing it as English doesn't work. But each sound has one letter and each letter has one sounds, so once you know the sounds you very much just pronounce it like it's spelled.
The Duolingo administration decided not to provide audio for the Klingon course at first (which has been true for a few of their more atypical languages). The Contributors and Moderators would love to add it and Duolingo is working on a method that might allow us to do it, but even when they add the ability, it's going to take us a long time to add audio for many of the sentences.
There is a Skill a little bit into the course which teaches the names of the Klingon letters and has a description of the pronunciations in the Tips & Notes, however, that skill also lacks audio. If you want to check out some ideas for learning the pronunciation, check out the thread at: https://forum.duolingo.com/comment/26605745
If you want to read about the other known issues in this course, read the post at: https://forum.duolingo.com/comment/26778885
I forget, is nuqneH used as a form of greeting like, "how are you?" or do we take it literally?
Klingons don't "do" greetings or good-byes.
They come up to you, get straight to the point and state their business, then leave.
If a Klingon comes up to you and just stands there speechless, you might prompt them with nuqneH? "Whaddayawant?".
But it's not a ritual greeting that you use whenever you meet someone. (And especially not if you're the one who is walking up to someone else.)
(Similarly, while it's possible to say things such as "Are you healthy?" or "The sun is shining." or "When you consider our ball throwers, what do you think?", that doesn't mean that Klingons engage in such small-talk.)