I flew back from NRT to ORD this Monday. I had two hour connection time. But my NRT-ORD flight was delayed by ~1 hr. I kept checking UA app. I was first protected for a UA flight leaving next morning. Later, I was protected on an AA flight leaving later in the evening. Fortunately, I made the connection with the help of One-Stop (for pax with carryon luggage only), train to Terminal 1 and empty security line at Terminal 1. I did not call UA during my dash to Gate C30 from the international terminal.