At Deloitte, you could be expected to plan, prepare, and deliver presentations to clients or other stakeholders. As most of us know, public speaking can be intimidating. It's okay to be nervous; however, the interviewer wants to see that these nerves do not hinder your preparation and ability to communicate well.
If you know ahead of time that presentations will be a part of this position, feel free to bring a previously crafted PowerPoint presentation with you on a tablet or iPad. Otherwise, be prepared with examples that include the number of people you have presented to, the range of topics, and the outcome.
You can also make your answer very clear by rating yourself from 1-10 on your PowerPoint and public speaking skills. If you have any formal training in public speaking, be sure to mention that.