Núñez has nine goals and five assists in 24 matches this season.
However, Al-Hilal recently chose to drop Núñez from their Saudi Pro League (SPL) squad after signing Karim Benzema.
Each team is only allowed to register eight foreign players for the SPL. Right now, Núñez is only allowed to play in the AFC Champions League.
The decision has led to speculation that former Liverpool striker Núñez could leave Al-Hilal and there have been rumours of interest from Newcastle and Tottenham.
Now ChronicleLive reports that Chelsea are pursuing Núñez ahead of the summer transfer window.
The 26-year-old is said to prefer a move back to the Premier League if he leaves Al-Hilal.
Newcastle are still in the hunt, despite the fact that Nick Woltemade and Yoane Wissa were signed last summer.