Generally broadcast order is the order you want to watch things, because that's how the story was written. Prequels have call-backs (forwards?) to things that happen later in-universe, some stories will be more interesting if you understand their significance as background to a larger epic, etc.
Watching stories in in-universe chronological order is a fun idea and can give you some new perspectives, but it will be more enjoyable if you've already seen it all once.