Yes i'm Norwegian. Sure i can recommend lots of good books, but when i try to find them in amazon it seems few of them are translated.
When looking at norwegian literary history you cant get past
"The four greats", Bjørnstjerne Bjørnson, Jonas Lie, Henrik Ibsen and Alexander Kielland. Four very influential writers in their time. But in my opinion Bjørnstjerne Bjørnson and Jonas Lie feels very dated when reading them today. Alexander Kielland is less known outside the borders of Norway, but i like him and can recommend Skipper Worse or Poison if you can find them in english.
I can also recommend
Aksel Sandemose, especially "A fugitive crosses his tracks". Sigurd Hoel is another good writer from the same period, but it looks like very few of his books are available in English. His most famous book is called "Sinners in summertime" but i feel it has more to do with the time it was released and not the books itself. I prefer "fourteen days before the frostnights", but i dont think its translated.
Agnar Mykle has a couple of good books, in particular Lasso around the Moon.
Jens Bjørneboe is another interesting author, though his early socially critical novels are of limited interest these days, especially if you dont live in norway. I can recommend the triology "The history of Bestiality" (Moment of freedom, Powderhouse, The silence) and "The sharks".
I dont read that much contemporary Norwegian literature but Erlend Loe is a interesting author, if you like his peculiar writing style. Try
Naive. Super .