Ultra nationalism might be defined as a nationalism that turns to discrimination and/or violence as means to confirm national superiority over outsiders and other nations in general.
You have examples of that in Mussolini's fascism, in Italy.
A rarely used example of the case is the Japanese ultra nationalism under the during the era of the emperor Hirohito, who was not involved in politics, leaving the command of the nation to the Japanese military leaders.
You can also find examples during the World Wars in Canada and the USA, considering the concentration camps where both countries left people of Japanese descent. In Canada, during the WWI, they even sold the properties of the Japanese Canadians to pay for the concentration camps.
