Titanic reference's significance in Batman TAS episode "Prophecy of Doom"

Yes, the episode is intentionally evoking the sinking of the Titanic, but referencing earlier depictions of the disaster (an event which has inspired no less than 15 feature films and countless TV shows), rather than the 1997 film "Titanic", which it obviously predates by several years.

The Unsinkable Titanic (Harry Lloyd King - painted 1912)

Lower the Boats! (from the movie A Night to Remember - 1958)

Pull Away, you dogs! (Litho-Print - Untergang der Titanic by Willy Stöwer, painted 1912)

You may also want to note the ship's highly distinctive livery and unusual 4-funnel design.

As far as the episode itself is concerned, there don't appear to be any in-universe references (within the script) to the Titanic, only the images, which I'm assuming the makers would be pleased that you recognised.

The ship that capsized and sunk is a generic luxury liner, a cruise ship like any other. It sinks the same way any ship with a hole from an explosion would (Takes in water, water heavy end sinks, lifting the far end into the air).

While it might be reminiscent of the Titanic, unlike the Titanic, there is no ice burgs, no people swimming in the ocean. The plot has nothing to do with the Titanic as well. The ship is just one occurrence of Nostromo's ""future telling ability"".

Also note that The Titanic movie was released in 1997, while this episode was from 1992.

As Lisa Clark says in the episode, it's just a coincidence.