A month with a broken leg could be hard on the nerves (6)
I believe the answer is:
jangle
'be hard on the nerves' is the definition.
I can't tell whether this definition defines the answer.
'a month with a broken leg' is the wordplay.
'a month' becomes 'jan' (abbreviation for January).
'with' means one lot of letters go next to another.
'a broken' indicates anagramming the letters.
'leg' with letters rearranged gives 'gle'.
'jan'+'gle'='JANGLE'
'could' is the link.
Can you help me to learn more?
(Other definitions for jangle that I've seen before include "Cacophony" , "Unpleasant ringing noise" , "contention" , "(Of nerves) be set on edge" , "clink" .)