The Chinook, and it's smaller brother, the CH-46 are helped immensely by a very capable automatic flight control system that provides attitude hold. Basically, when you have the attitude you want and have trimmed up the cyclic and pedals, the system will hold that until you run out of gas.
But even with the AFCS off, it is still quite easy to hover - helped not only by the lack of torque reaction, but also by the lack of side force and roll changes with tail rotor changes required by power changes.