Adding markup inside first list item of main-menu
I managed to apply the code only to the item in the main-menu by introducing a condition of menu-name and #href:

function mymodule_preprocess_menu_link(&amp;$vars) {
  $element = &amp;$vars['element'];
  $my_view = views_embed_view('view_name', 'display_id');
  if(strpos($element['#href'], 'home') !== false &amp;&amp; $element['#original_link']['menu_name'] == 'main-menu')
  {
    $element['#below']['#markup'] = $my_view;
  }
}