the Klingon word {nuq} is a noun. It’s never anything but a noun.

The Klingon word nuq is a chuv. it's never anything but a chuv. However, it can stand in for a noun. We have a term for words that stand in for nouns: pronouns. And we know something else about Klingon pronouns: they can be used in copulas, where one word gets identified with another word. yIH nuq?

You can’t use it in any question that tries to ask a question that is not answered by the statement formed by repeating the question with {nuq} replaced by the noun it stands for.

In basic sentences, this is correct, and I believe your reasoning for why jarlIj qaq nuq doesn't work is also correct. However, it is not generally true, as the answer to yIH nuq cannot be yIH Ha'DIbaH 'up.

-- 
SuStel
http://trimboli.name