On July 13 2011 Shane O'Hare was offered the food by a female manager who also told him 'micks at one end, oranges at the other'.
Mick is a slang and derogatory term for Roman Catholics and the incident was one day after the famous July 12 parade.
In the mid 1990's the Orange Order was banned for walking past Drumcree Parish Church which sparked mass protests.
Mr O'Hare's allegation that the phrase was used to insult his Catholic belief was accepted by the tribunal.
"We regard all three incidents as amounting to harassment of the claimant on grounds of his religion," the tribunal said.
In announcing its decision it added: "We find the explanation for the name of the chicken dish to be disingenuous to say the least, as it ought to have been clear that the naming of a dish in that way, on that day, to a Roman Catholic, clearly had the capacity to cause offence."
Tribunal judges said the discrimination had comprised of 11 separate events including a union flag being drawn on his hospital file.
Employers South Eastern HSC Trust said it was "disappointed" with the tribunal's findings.
A spokeswoman said: "The Trust would refute that there is a culture of toleration of sectarian behaviour in any of our hospitals, but we will take immediate action to remind all staff of the importance of preserving a neutral working environment.
"The Trust only received the tribunal report on 26 November 2014 and we are considering the points contained within this and will take appropriate action."