Remove nbsp

function.php

<?php
function replace_nbsp_in_posts() {
    global $wpdb;

    $query = "
        UPDATE {$wpdb->posts}
        SET post_content = REPLACE(post_content, CHAR(160), ' ')
        WHERE post_content LIKE '%" . chr(160) . "%'
    ";

    $result = $wpdb->query($query);

    if ($result !== false) {
        return "Successfully replaced non-breaking spaces in $result posts.";
    } else {
        return "Failed to update posts.";
    }
}

// Run the function only when needed
add_action('admin_init', function() {
    if (current_user_can('manage_options') && isset($_GET['replace_nbsp'])) {
        echo '<div class="updated"><p>' . replace_nbsp_in_posts() . '</p></div>';
    }
});