Nest egg letters (3)
I believe the answer is:
ira
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">nest egg letters</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 ira that I've seen before include "nationalists" , "George Gershwin's older brother, the lyricist" , "Illegal organisation, initially" , "Songwriter George's elder brother" , "Militant republicans" .)