The most common and most likely answer to this crossword clue is the 8 letter word CORDOBAS
I've seen this crossword clue in The Guardian
C
O
R
D
O
B
A
S
Buddy explains!

The straight part
We know that "Nicaraguan capital" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case nicaraguan capital = cordobas.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 CORDOBAS mean?
CORDOBAS noun- The currency of Nicaragua, divided into 100 centavos.