She surrendered completely. Nynaeve overcoming her block in Ebou Dar. As a wilder, she learned how to channel by instinct, giving rise to a style of Healing unknown to any living Aes Sedai.

Does Nynaeve ever break her block?

Nynaeve's fear and desperation as she sank into the river, on the very edge of consciousness, she surrendered to her impending death. With that true and utter surrender, she broke her block and channeled her way to escape and survival.

Does Nynaeve learn to channel without being angry?

Finally, just as she is about to lose consciousness, she surrenders to saidar completely for the first time and is able to channel without being angry—her block is gone. She breaks free of the sunken ship and tries to swim to the surface.