Cranny's cousin
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cranny's cousin</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for nook that I've seen before include "Secluded recess" , "Recess or cranny" , "Comfy corner" , "Hidey-hole" , "Interior angle formed where two walls meet" .)