Nynorskkorpuset is an electronic collection of Nynorsk texts and encompassing about 74 million words. The corpus contains fiction, newspaper texts, journal articles, textbook texts, religious texts and texts from the public target user. Collected texts cover the period from the 1870s to the present day, with the main emphasis on the last fifty years.
See more about the corpus at http://no2014.uio.no/korpuset/ (in Norwegian)
Found detailed tagset summary at http://folk.uio.no/danielr/nyno-brill-doc.html