The most common and most likely answer to this crossword clue is the 5 letter word PRIES
I've seen this crossword clue in Financial Times
P
R
I
E
S
More clues leading to the result PRIES
Buddy explains!

The straight part
We know that "sticks his nose in" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sticks his nose in = pries.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 PRIES mean?
PRIES verb- To look where one is not welcome; to be nosy.
- To keep asking about something that does not concern one.
- To look closely and curiously at (something closed or not public).
- To use leverage to open or widen.