Corruption of niece’s MP, for example (8)
I believe the answer is:
specimen
'example' is the definition.
(specimen is a kind of example)
'corruption of niece's mp' is the wordplay.
'corruption of' is an anagram indicator.
'nieces'+'mp'='niecesmp'
'niecesmp' is an anagram of 'SPECIMEN'.
'for' is the link.
(Other definitions for specimen that I've seen before include "Test sample" , "Derogatory description of person" , "Copy" , "Person critically" , "Object serving as an example of its class" .)