I've never heard of Chasen's here in NY. Are you
thinking about the one in Los Angeles ??
For dinner after theatre, I would suggest you NOT eat
in the Theatre District (unless you must). There are
so many other places that serve late, and have much
better food. Let me know what kind of food and price
range, and I and the other inhabitants of this board
will be happy to help.
If you must eat in the Theatre District, may I suggest
either Becco or Frico Bar.