Borcas is an unseen character in Game of Thrones. He is a member of the Night's Watch, and apparently chief among the stewards stationed at Eastwatch-by-the-Sea.
When the newly graduated recruits are assigned to their orders Dareon is told by Maester Aemon to report to Borcas at Eastwatch-by-the-Sea, and warned not to comment on his nose.
In the books
In the A Song of Ice and Fire novels Borcas is also mentioned, however the book makes no description whatsoever about his nose.
Borcas at A Wiki of Ice and Fire