I think I would recommend really spend time practicing how you introduce your research, from bigger picture to aims to results and significance, and make sure to prepare two versions of diff length so that you can be more flexible (I prepared a shorter elevator pitch like version and a longer detail explanation).
And don't be nervous!!! For my interviews, mostly I spent 20-25 mins talking about my research projects, so you actually don't have that much time discussing their research. make sure you understand what they do in general, and just treated as a normal casual conversation (i.e. maybe prepare some questions that you're genuinely curious about)!!
I'm also an international student so no worries!! Getting an interview offer means you're great candidate so no need to be nervous~