The 21-year-old, who has previously had loan spells at Middlesbrough and Coventry, becomes Ian Holloway's first signing since taking over at Selhurst Park in November.
And Nimely has revealed that Holloway has had his eye on the Liberia-born player for some time.
He told the club's official website: "I've played against Blackpool and Crystal Palace a couple of times so I think the manager has been watching me for a long time so when he gave me the call to come here I was very happy to.
"The lads are all good and they've welcomed me well. I trained last week before the game against Stoke and I watched that game and was shocked by the way they play football by keeping the ball on the floor.
"I met the manager and he's fantastic. His philosophy is great as he wants to play good football and help the young players improve."
Holloway added: "I've admired him for a couple of years, I like his movement, skill and his tenacity. I want him to play for us and get some goals and hopefully he'll do that.
"He's a nice kid and he's one of the ones that they tend to stack and rack at clubs like Manchester City and I'm very pleased that with the choices he had he's chosen us."