With the recent reveal that Steve Rogers is going to become the Nomad after the events of Captain America: Civil War I have decided to explain the identity of the Nomad.
In the comics the Nomad is Steve Rogers’ new identity after he abandons the Captain America title. He adopts this new identity when he becomes disappointed with the United States government. However this identity only lasted for four comic book issues before he went back to the identity of Captain America. It will be interesting to see in the movies if or when Steve Rogers goes back to the Identity of Captain America.