Eagles boss Vieira wanted to bolster his attacking line in this window as on-loan striker Jean-Phillippe Mateta was struggling with his form at the club.
Arsenal starlet Nketiah emerged as their top target and Palace saw the Gunners knock back a bid for him.
Mateta has found his rhythm in front of goal in recent games and the London outfit are now pushing to make his move permanent from German side Mainz.
Crystal Palace are also set to welcome back Wilfried Zaha following his participation in Africa Cup of Nations, while hitman Christian Benteke is not leaving Selhurst Park this month.
And with all three of Mateta, Benteke and Zaha set to be available for the remainder of the season, Crystal Palace are unlikely to make any moves to bring in a forward, even though Nketiah has remained on their transfer radar.
The Eagles have shifted their focus to reinforcing midfield and are now closing in on a loan swoop for Donny van de Beek from Manchester United.
Meanwhile, Nketiah is out of contract at Arsenal next summer and is set to be available on a free transfer; he is also attracting interest from Germany.
