At the beginning of his second stint at Luton in 2008, in which he dropped two divisions to play, Nicholls stated that his main motivation for returning was his love for the club.
[3] A long-term knee injury sustained in 2009 led to him volunteering to be released from his contract on 27 August 2010 and he subsequently retired from professional football.
[4] Born in Upton Park, London, Nicholls began his playing career at Charlton Athletic, making his debut in the 1996–97 season as a substitute in a 2–1 loss to Ipswich Town.
[6] After a short period back at Charlton, Nicholls was transferred to Wigan Athletic, then in the Second Division, in the summer of 1999 for £250,000, rising to £650,000 based on appearances.
At Luton, Nicholls managed for several seasons to avoid the injuries that dogged him at previous clubs and became the "heart and soul of the team" according to Kinnear.
The Hatters eventually fell short of the quality to see out the game, losing 5–3, but many of the players, such as Nicholls, who had spent the majority of their careers in the lower leagues, were now in the public eye.
[10] Nicholls' quick rehabilitation allowed him to make his debut for the club as a substitute in Leeds' match against Sunderland on 13 September 2006, over a month before he was due back.
Nicholls missed much of the 2008–09 season as a result of recurring injury problems, but returned fully fit in the final run-in of games.
On 24 March 2009, he was given a five-game ban and £1,000 fine for supposedly applauding Luton fans for throwing missiles at the referee after a controversial 3–3 draw with Bradford City.
[17] On 5 April 2009, Nicholls captained Luton to a 3–2 victory over Scunthorpe United at Wembley Stadium in the Football League Trophy final, picking up the man-of-the-match award for his performance in the heart of midfield.
[18] He played for Luton in their 0–0 draw with Chesterfield on 13 April, which saw them lose their Football League status and suffer relegation to the Conference Premier.
It was later revealed by Luton director Gary Sweet that Nicholls had deliberately downplayed the seriousness of this injury to lead the team, "playing through excruciating pain and ultimately risking his long term health".