Sure thing. ikegami's suggestion is probably the most portable way to handle it too. It skips some of the node nonsense (naked text between elements are nodes|children too) and it is the way I usually do it in code. This would remove any after the first of a given TAGNAME.

my @nodes = $doc->findnodes("//TAGNAME");

if ( @nodes > 1 )
{
    $_->getParentNode->removeChild($_) for @nodes[1..$#nodes];
}
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