The most common and most likely answer to this crossword clue is the 5 letter word KHOUM
K
H
O
U
M
Buddy explains!
The straight part
We know that "change turning up in Nouakchott" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case change turning up in nouakchott = khoum.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does KHOUM mean?
KHOUM noun- A subdivision of the Mauritanian ouguiya. 5 khoums equal one ouguiya.