Obvious that we both have access to the same census scan website. I felt their assumption of a middle initial W in 1900 was highly doubtful - after all the scribbling right on top of the letter itself. But the 1910 was as clear as day and I agree with you - the letter N it is!
So taking his first name, the likely first letter of his patronymic (N), a range for birthyear (I usually include plus and minus a year or two), and a vague idea of the name of the farm in Norway we'd LIKE to find him living on - I used the following database search for the 1865 Norwegian census.http://www.rhd.uit.no/folketellinger/folketellinger_avansert...
By asking that search to return name of 'domicile' in any results - I found a Hans Nilsen of the right age category living on a farm spelled as "Vinnæs" in Øvre Eiker district of Buskerud, Norway on the 1865 Norwegian census. I think he'd be well worth your time in more detailed research.
The same young man was found leaving from the port of Oslo/Kristiania in 1884 (source - Digitalarkivet emigration databases).