Complex sentence: A moderately successful jump jockey, Nicholls has become the leading National Hunt trainer of his generation finishing the 2007-2008 season with 155 winners and a record £4 million in prize money.
Split into simpler sentences: A moderately successful jump jockey, Nicholls has become the leading National Hunt trainer of his generation. His career reached its zenith in the 2007-2008 season with 155 winners and a record £4 million in prize money.