As we discuss in "Tone," the Chorus plays a large part in establishing the tone of the play. In many ways, this group of women guides the audience as to how to react to the action on stage. In this case, we see that the Chorus sympathizes with Electra. The Chorus agrees that she's been treated terribly since her father died, and they lament her situation. They share her grief when she thinks that Orestes is dead, and her joy when he shows up alive.
But the Chorus also gives Electra a hard time, especially at the beginning of the play when she debates with Chrysothemis about how to live their lives in light of their father's murder. The Chorus actually takes Chrysothemis's side – they encourage Electra to move on like her sister, to start thinking pragmatically instead of idealistically. This tension is important – the Chorus doesn't just reiterate Electra's ideas here.