Even though Ronaldo is the main target for Al Nassr at the moment, that does not reduce Talisca's sharpness and how important he is at the club, he has scored 4 goals and 2 assists, and 4 other goals in different competitions. Talisca has managed to appear consistently, maybe he won't be Al Nassr's top scorer again this season, but without him Al Nassr is very likely to experience problems in attack, so keeping him at the club is no less important than keeping Ronaldo.
Right now, Al Nassr is experimenting with the combination of Cristiano Ronaldo-Sadio Mané-Talisca-Otávio, and it was worked very well so far. They have won 6 matches consecutively as of now, and that includes matches against tough opponents such as Al Ahli and Al Shabab. My only concern here is about injuries. Cristiano Ronaldo is 38 years old and he maybe prone to injury. The same can be said about Sadio Mané as well. He missed Qatar 2022 as a result of injury (which he suffered during the match between Bayern Munich and Werder Bremen).