I don't remember the last time I could visit nickelodeon.nl The Flemish website launched in 2003 and it didn't take long before the Dutch website got geoblocked here. It is odd that the Belgian website didn't get geoblocked in the Netherlands!Sorry for the double post.
Nick's now merged nickelodeon.be with nickelodeon.nl.
The Flemish schedule can now be found here: Nickelodeon TV-gids | Shows, afleveringen | Nickelodeon Vlaanderen