Hard-coding a shortcode as the last menu item in primary navigation?

I have Genesis framework installed with a child theme.
My client wants their themes “shopping cart” shortcode to be the last menu item, in their primary nav, no matter how many menu items there is.

The shortcode:

echo do_shortcode('[shopping_cart]');

Current code:

        $nav_output = sprintf
( '<div id="nav">%2$s%1$s%3$s</div>', $nav, genesis_structural_wrap( 'nav', '<div class="wrap">', 0 ), genesis_structural_wrap( 'nav', '</div><!-- end .wrap -->', 0 ) );

        echo apply_filters( 'genesis_do_nav', $nav_output, $nav, $args );

    }

}

Current output:

<div id="nav">
<div class="wrap">
<ul id="menu-main-navigation-menu" class="nav">
<li id="menu-item-91" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-91">
<li id="menu-item-29" class="menu-item menu-item-type-post_type menu-item-object-page menu-item-29">
<!-- this is where the shortcode should be placed, just before closing the list -->
</ul>
</div>
</div>

Solutions Collecting From Web of "Hard-coding a shortcode as the last menu item in primary navigation?"

add_filter('wp_nav_menu_items','my_item', 10, 2);
function my_item($items, $args) {
    $items .= '<li class="myclass">whatever</li>';
    return $items;
}

If you have a specific theme location for menu you can target it with :

if( $args->theme_location == 'mylocation' )

EDIT I

you can try

$items .= '<li class="myclass">' . echo do_shortcode('[shopping_cart]') . '</li>';

but it will work only if the function is available.
About the product No. – I have no idea until I see the code that produces it .

Try this, w/dropdown

function my_contact_item($items, $args) {
  if( $args->theme_location == 'primary' )
    return $items . '<li class="myclass"><a href="http://example.com">My link title</a><ul class="sub-menu"><li><div style="width:350px;">' . do_shortcode('[My_Shortcode]') . '</div></li></ul></li>';
}
add_filter('wp_nav_menu_items','my_contact_item', 10, 4);

without dropdown

function my_contact_item($items, $args) {
  if( $args->theme_location == 'primary' )
    return $items . '<li class="myclass"><a href="http://example.com">My link title</a>' . do_shortcode('[My_Shortcode]') . '</li>';
}
add_filter('wp_nav_menu_items','my_contact_item', 10, 4);