Due to a broken ankle, he missed the entire summer circuit prior to his senior season.

He made 25 starts out of 30 games played and led all freshmen nationally in field goal percentage (.602) and blocks (81).

He ranked 18th nationally, and second in the A-10, in field goal percentage at .564 (198–351), the ninth-best season total in program history.

He scored a season-high 29 points on two separate occasions, the first of which came on 11-of-13 shooting from the floor with a career-best 14 rebounds against Norfolk State on November 28; second came at Duquesne on January 23, where he played the full 40 minutes.

He became the 38th player in school history to surpass the 1,000-point barrier with a foul-line jumper in the first half of the Niagara game on December 11, 2010.

He scored a career-high 44 points, on 14-of-19 field goals and 16-of-25 from the free throw line, while pulling down 12 rebounds in a four-overtime thriller against Ohio on December 18, the longest game in SBU history.

[6] Nicholson made his regular season debut on November 2, 2012, against the Denver Nuggets, coming off the bench to record 2 points, 2 rebounds, 1 assist and 1 block in a 102–89 win.

[7] He made his first career start on December 21, 2012, against the Toronto Raptors in place of the injured Glen Davis.

[18] After going scoreless in four straight games in mid-January, Nicholson was dropped from the rotation and did not play against the Philadelphia 76ers on January 20, 2016, his first DNP since November 14, 2015.

[23][24] He made his debut for the Wizards in their season opener on October 27, recording nine points and seven rebounds off the bench in a 114–99 loss to the Atlanta Hawks.

[25] On February 22, 2017, Nicholson was traded, along with Marcus Thornton and a 2017 first-round draft pick, to the Brooklyn Nets in exchange for Bojan Bogdanović and Chris McCullough.

[34] On June 30, 2021, Nicholson joined the Daegu KOGAS Pegasus of the Korean Basketball League (KBL).

In October 2023, Nicholson rejoined the Daegu KOGAS Pegasus to replace Isaiah Hicks after Bay Area Dragons dismissed.