The Nobel Prize has slightly more specific language in its requirement, stating that it will be awarded, by the Royal Swedish Academy, to an author who produces
"in the field of literature the most outstanding work in an ideal direction."
Note that the word “work” here does not refer to a one specific piece of writing, but to a body of work. Also, the word “ideal” can be interpreted in different ways, so over the years, the committee that awards the prize has tended to lean in different directions. In recent years, most authors under consideration have produced work that concerns itself with human rights in some way.
The Booker Prize is awarded on the basis of a more general requirement. According to the organization's webpage,
The Man Booker International Prize recognises one writer for his or her achievement in fiction.
Again, the award is given for a body of work, not just one book. However, it is required that the book has been published in English, a requirement the Nobel Prize does not share. The prize winner is determined by a panel, which has members from the international community, while all of the members of the Nobel committee come from the Royal Swedish Academy.