I am not sure if this question is on topic here but I will give it a try. According to the Nobel Nomination archive official website, nomination data cannot be "revealed until 50 years later" at least. Peace and Literature Prizes are updated up to 1971. Physics Prize nomination archives are revealed up to 1970. Why don't we have information on 1971, 1972 and 1973? Medicine is even worse because it is stuck at 1953 for no clear reason.
For prizes older than 50 years old, you can browse the nomination archive. Note that in some cases the archives are sealed as long as people mentioned are still alive.
At first I though that the nominees should be deceased in order for the information to be released but people like Jeffrey Goldstone (nominated in 1968) are still alive. Maybe this condition is about the nominators?
What restricts a new year of nominations to be revealed each year? Do we know how often the archives get updated?