Nominal source of the confusion about a police inspector! (5)
I believe the answer is:
edith
'nominal source' is the definition.
The definition suggests a singular noun which matches the answer.
'the confusion about a police inspector' is the wordplay.
'confusion' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'a police inspector' becomes 'di' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'the' anagrammed gives 'eth'.
'eth' placed around 'di' is 'EDITH'.
'of' is the link.
Can you help me to learn more?
(Other definitions for edith that I've seen before include "Woman" , "Woman's name" , "- Cavell, WW 1 heroine" , "- Cavell, nurse executed in 1915" , "Evans, Sitwell or Piaf" .)