As a NES, but not a teacher, I'm afraid that I haven't come across the expression: "every nook and corner" before, but what I have come across (and used) is a similar expression: "every nook and cranny", which would mean the same.
See: every nook and cranny: - Idioms - by the Free Dictionary, Thesaurus and Encyclopedia.
"every part of a place" including "every small, out-of-the-way place or places where something can be hidden".
In your case it would mean every small extremity of the location involved.
Hope this helps
Student or Learner