When no WooCommerce products are found, show the visitor your features products

functions.php

<?php
add_action( 'woocommerce_no_products_found', 'show_featured_products_on_no_products_found', 20 );
function show_featured_products_on_no_products_found() {
	echo '<h2>' . __( 'You may be interested in...', 'domain' ) . '</h2>';
	echo do_shortcode( '[featured_products per_page="4"]' );
}