<?php

$obj = new stdClass('Chats');

$chat_obj_0 = new stdClass();
$chat_obj_0->ChatId = 133831;
$chat_obj_0->UserId = "a2784a6dcf1";
$chat_obj_0->SystemId = "a2784a6dcf~a2784a6dcf_OVL1";
$chat_obj_0->Fullname = "chris 1";
$chat_obj_0->Email = "sadsad1@gmail.com";

$chat_obj_1 = new stdClass();
$chat_obj_1->ChatId = 133832;
$chat_obj_1->UserId = "a2784a6dcf2";
$chat_obj_1->SystemId = "a2784a6dcf~a2784a6dcf_OVL2";
$chat_obj_1->Fullname = "chris 2";
$chat_obj_1->Email = "sadsad2@gmail.com";

$n1 = (object) ['Chat' => $chat_obj_0];
  
$n2 = (object) ['Chat' => $chat_obj_1];


$obj->Chats = array(
    0 =>  $n1,
    1 =>  $n2
  );


foreach($obj->Chats as $item) {

 	   echo 'Chat ID: ' . $item->Chat->ChatId . ' e User ID: ' . $item->Chat->UserId . "\n";
}

print_r($obj);