In a rematch of the 2017 Gold Cup final won by USA, Jamaica emerged triumphant courtesy of Nicholson's first international goal at Audi Field.
Nicholson came off the bench and beat Zack Steffen with a memorable strike from outside the penalty area in Washington as both teams stepped up their preparations for the upcoming tournament.
Playing without Chelsea-bound star Christian Pulisic as coach Gregg Berhalter gave players a chance to stake their Gold Cup claims, USA made a strong start but struggled afterwards.
USA put Jamaica, which had Bayer Leverkusen star Leon Bailey among the substitutes, on the back foot during the early exchanges – the host enjoying success down the right side.
However, Jamaica eventually settled into its rhythm as the half petered out, with neither team creating any clear-cut chances.
Jamaica looked the more likely to score as the match wore on after Peter-Lee Vassell almost broke the deadlock with a curling effort in the 56th minute.
But Jamaica got the goal they deserved thanks to substitute Nicholson in memorable fashion four minutes later.
Nicholson cut inside and back out again before firing a stunning long-range shot past Steffen, who is set to join Manchester City before reportedly heading to Fortuna Dusseldorf on loan.