how to reverse "next portfolio item" from left to right

I figured it out. Hopefully this will help someone. I had to piece together a few threads to figure this out. The code that needs to be changed is in “functions-enfold.php” but I didn’t want my changes to be overwritten by a theme update so I copied the entire “avia_post_nav” section from “functions-enfold.php” into the “functions.php” file of my child theme because apparently “functions-enfold.php” file is not recognized in child themes and I learned you can copy functions from functions-enfold.php into the the function.php file, which is recognized by the child theme.

So, I copied this entire section from functions-enfold.php into child theme functions.php:

if(!function_exists('avia_post_nav'))
{
	function avia_post_nav($same_category = false, $taxonomy = 'category')
	{
		global $wp_version;
	        $settings = array();
	        $settings['same_category'] = $same_category;
	        $settings['excluded_terms'] = '';
			$settings['wpversion'] = $wp_version;
        
		//dont display if a fullscreen slider is available since they overlap 
		if((class_exists('avia_sc_layerslider') && !empty(avia_sc_layerslider::$slide_count)) || 
			class_exists('avia_sc_slider_full') && !empty(avia_sc_slider_full::$slide_count) ) $settings['is_fullwidth'] = true;

		$settings['type'] = get_post_type();
		$settings['taxonomy'] = ($settings['type'] == 'portfolio') ? 'portfolio_entries' : $taxonomy;

		if(!is_singular() || is_post_type_hierarchical($settings['type'])) $settings['is_hierarchical'] = true;
		if($settings['type'] === 'topic' || $settings['type'] === 'reply') $settings['is_bbpress'] = true;

	        $settings = apply_filters('avia_post_nav_settings', $settings);
	        if(!empty($settings['is_bbpress']) || !empty($settings['is_hierarchical']) || !empty($settings['is_fullwidth'])) return;
	
	        if(version_compare($settings['wpversion'], '3.8', '>=' ))
	        {
	            $entries['next'] = get_previous_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	            $entries['prev'] = get_next_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	        }
	        else
	        {
	            $entries['next'] = get_previous_post($settings['same_category']);
	            $entries['prev'] = get_next_post($settings['same_category']);
	        }
	        
		$entries = apply_filters('avia_post_nav_entries', $entries, $settings);
        $output = "";

		foreach ($entries as $key => $entry)
		{
            if(empty($entry)) continue;
			$the_title 	= isset($entry->av_custom_title) ? $entry->av_custom_title : avia_backend_truncate(get_the_title($entry->ID),75," ");
			$link 		= isset($entry->av_custom_link)  ? $entry->av_custom_link  : get_permalink($entry->ID);
			$image 		= isset($entry->av_custom_image) ? $entry->av_custom_image : get_the_post_thumbnail($entry->ID, 'thumbnail');
			
            $tc1   = $tc2 = "";
            $class = $image ? "with-image" : "without-image";

            $output .= "<a class='avia-post-nav avia-post-{$key} {$class}' href='{$link}' >";
		    $output .= "    <span class='label iconfont' ".av_icon_string($key)."></span>";
		    $output .= "    <span class='entry-info-wrap'>";
		    $output .= "        <span class='entry-info'>";
		    $tc1     = "            <span class='entry-title'>{$the_title}</span>";
if($image)  $tc2     = "            <span class='entry-image'>{$image}</span>";
            $output .= $key == 'prev' ?  $tc1.$tc2 : $tc2.$tc1;
            $output .= "        </span>";
            $output .= "    </span>";
		    $output .= "</a>";
		}
		return $output;
	}
}

and then, replaced this:

{
	            $entries['prev'] = get_previous_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	            $entries['next'] = get_next_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	        }
	        else
	        {
	            $entries['prev'] = get_previous_post($settings['same_category']);
	            $entries['next'] = get_next_post($settings['same_category']);
	        }

with this:

{
	            $entries['next'] = get_previous_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	            $entries['prev'] = get_next_post($settings['same_category'], $settings['excluded_terms'], $settings['taxonomy']);
	        }
	        else
	        {
	            $entries['next'] = get_previous_post($settings['same_category']);
	            $entries['prev'] = get_next_post($settings['same_category']);
	        }

Now, when I sort my portfolio chronologically by date, I have my newest stuff at the top and when someone opens one and clicks on the right navigation arrow, they can navigate through the portfolio in the order they appear on the page. Intuitively, most people want to click the right arrow to navigate what they perceive to be forward, through the portfolio.

If you care to, you can preview it in action on my site here: