One sticking point I see with this question is that the "choragus" refers not to the dramatic Chorus but rather to the group of wealthy Athenian citizens who acted as producers for theatrical productions, which were always related to state religious holidays and performed as part of highly competitive--and highly lucrative--festivals. The play that won would receive quite a monetary reward that would be given to--the choragus: choagus is plural for choragi: wealthy citizens who paid the cost of productions including the hiring, costuming, and salaries of the Chorus. I find no alternative definition or usage for choragus.
Therefore, if the choragus were to say something to Jocasta after her suicide, it would probably be along the lines of: "Your performance was weak. Don't peek after killing yourself. Next performance get your wig on straight. You're on again for tomorrow's matinee. Break a leg!"
If what you actually mean is something like, "What would the Chorus Leader say to Jocasta afterward?" (aside from the tricky semantics thing of her suicide making it impossible to say anything to her), then it would be something reflecting the last thing he said to her and the next significant thing he said after her death; these things are:
CHORUS LEADER: Why has the queen rushed off, Oedipus,
so full of grief? I fear a disastrous storm
will soon break through her silence.
CHORUS LEADER: An awful fate for human eyes to witness,
an appalling sight—the worst I’ve ever seen.
O you poor man, what madness came on you?
What eternal force pounced on your life
and, springing further than the longest leap,
brought you this awful doom? Alas! Alas!
In these comments, the Chorus leader shows real understanding and compassion and sympathy. Therefore he would not say anything judgemental; he would not say anything dismissive nor condemning. He may say something like the following after his line that says:
CHORUS LEADER: That poor unhappy lady! How did she die?
"Sad Jocasta, mother of torn and sorrowful heart, with pain to the full as no other has felt. Woe drove her to her rest. Love drove her to her doom. Honor the beloved Queen, who sleeps now in quiet gloom."
It is a difficult one. I personally feel very sympathetic towards Jocasta. She is trapped in a hopeless situation where admitting the truth of what she suspects would result in an absolute nightmare for her. Death, in one sense, was the only way out. Who can blame her for a little bit of hubris in the process?
One purpose of the chorus in Greek tragedy is to be the voice of the "people" or the voice of the audience. You could ask yourself what YOU would say to her. Perhaps you would feel bad, but you could also note that the tragedy of the situation started when she and her husband tried to defy the oracle in the first place. That kind of hubris is always punished in Greek tragedy.
One clue may lie in the words of the messenger who announces the death of the queen:
SECOND MESSENGER: I’ll waste no words—
know this—noble Jocasta, our queen, is dead.
Notice that the messenger still calls Jocasta "noble," that he does not openly condemn her death (even though he knows its circumstances), and that he seems sorry about her death. Later he reports that "the poor woman suffered." He calls her a "poor woman" again a few lines later. In fact, the same phrase is used one more time in the messenger's speech. All this suggests that our attitude toward Jocasta is meant to be sympathetic and sorrowful, not harshly judgmental.
I guess the answer depends on whether or not you think Jocasta did the right thing. I think she felt disgusted and betrayed. It's her life, but who did she leave behind? Was her action justified? Was she just being selfish?