Just chiming in.

The concept behind the dragon king instead being called the great wyrm is likely due to a desire to convey intended meaning rather than litterally translating terms. To describe Nidhogg as a great wyrm is to add a layer of importance to his existence beyond simply being a king among dragons (a rather transient concept in western lore). I wouldn't be surprised if the Japanese term worked in a similar way within their own cultural connotations.

The German article indeed refers to "the ressurection of the dragon" rather than "the awakening of the great wyrm Nidhogg," so your comment is quite valid.

On a side note, I also suspect that the name Nidhogg is a reference to the being in Norse mythology that gnaws on the roots of Yggdrassil, the world tree. Much like Odin and Shiva etc are references to mythology themselves.