Lovie L,
With Nissen Surgery you normally receive general anesthesia. A endotracheal tube is a small flexible tube that is inserted into the mouth and down into the windpipe then attached to a ventilator. The tube is used to protect the airway and to assist a patient's effort to breathe. Sore throat following endotracheal intubation is a common problem after surgery and one of the factors that affects the quality of recovery. The soreness is caused by the insertion of the endotracheal tube through the mouth into the airway.
It should resolve in a few days if this is the cause of your sore throat.
Kindly,
Kitt