South American mountain chain (5)
I believe the answer is:
andes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">south american mountain chain</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for andes that I've seen before include "Peak District" , "Danes seen in mountains" , "Mountains in west" , "South American mountain system" , "Major mountain range" .)