Show product SKU when searching in WooCommerce

show-sku-search.php

<?php

/**
 * Show SKU on products when searching.
 */
function iconic_show_sku_search() {
	if ( ! is_search() ) {
		return;
	}

	global $product;

	$sku = $product->get_sku();

	if ( empty( $sku ) ) {
		return;
	}

	echo '<p>' . sprintf( '%s: %s', __( 'SKU', 'iconic' ), $sku ) . '</p>';
}

add_action( 'woocommerce_shop_loop_item_title', 'iconic_show_sku_search', 20 );