Order.php

<?php

namespace App\Nova;

use App\Nova\Actions\ExportOrders;

class Order extends Resource
{
    // snipped..

    /**
     * Get the actions available for the resource.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function actions(Request $request)
    {
        return [
            (new ExportOrders())
        ];
    }
}