Lucy Letby told a colleague she could offer her "tips" on how to get away with murder, the public inquiry into her crimes has heard.
Letby murdered seven babies and attempted to kill seven others at the Countess of Chester Hospital between June 2015 and June 2016.
Union representative Hayley Griffiths became friends with Letby when the nurse was moved off the neonatal unit and given office duties in 2016 after doctors raised concerns that she might have been harming babies.
A letter which Letby's parents sent to hospital bosses claiming she was being scapegoated for failings at the hospital was also read to the inquiry.