I'm not going to give up on Nadal yet, we all know he's getting kind of old and injuries affect tennis players a lot since it's a one player game, but he's not the type of player to give up easily, he had his downs throughout his career and bounced back, I'm expecting him to win a couple of big tournaments before he retires, if his body doesn't bring him down, the mentality to win will always be there with El Matador.
The major tournament that Nadal is still likely to win is the French Open, the only type surface that allows him to win lots of GS titles. This year's French Open will be held in May-June so Nadal has time to be able to recover from his injury even though the time that is still quite long is not a guarantee he will recover because it will really depend on the injury he experienced during the last Australian Open if it's too bad he might miss this tournament
Probably that will be his target at least for this year's GS. This is his favorite surface and has won than any player in history. But before he can do that, he will really have to rest his body and avoid such injuries even in the middle of the tournament.
Not sure if Alcaraz is also ready by that time, but I think he will be the biggest threat for Nadal this year in French Open.
So let's see, hopefully Nadal is going to be healthy so that we can still see if he can pull another win to get ahead of Djokovic then.