There is an irony to this question as you are the first person (I think) to ask about stopping the Cordyline australis (from New Zealand) from growing. Most questions on here are about winter frost damage that has killed the top!

Yes, Cordyline's can be chopped and though it looks severe, they will happily re-shoot lower down, usually from their base. Remember that there is already a large root ball so the resulting regrowth can be surprisingly fast compared to how long it originally took to get to the height it is now.

Just cut back in the spring a few years down the line to repeat this process.