What does the cryptic crossword clue "Nigel gets beaten up — he nicked someone's marbles (5)" mean?

The definition is "Nigel". The wordplay uses an anagram. anagram of NIGEL = ELGIN; definition: "he nicked someone's marbles" The answer is ELGIN.

Nigel gets beaten up — he nicked someone's marbles (5)

Guardian Cryptic #28958 | 4 Down | 2023-01-04 flower