Liverpool paid £64M to buy Nunez but they sold him for to Al Hilal for £46M. Liverpool lost money on his transfer fee. Nunez is a good striker he can score goals in the SPL. Al Nassr beat them in the Super Cup semi but Al Hilal will be a strong team for the SPL season.
Considering how terrible he was when he played there, I think losing that much is nothing, compared to sending him to some European team. If Liverpool tried to find a team around the European teams to sell him to, then they wouldn't get a dime more than 20 million. They got lucky that some Arabian team was willing to pay that much money for him, because he certainly doesn't worth that much.
In any case, Nunez did play there for many years, meaning they did not lose that much per season if you think about it. They now have a lot better players instead, and should be able to score a lot easier. Nunez missed so many goals, their wingers were higher scorers. The really hurtful one for Liverpool will be Diaz who went to Bayern, he was actually good and not terrible like Nunez.