This is a different kind of nervous than presenting to your own team or even a room of executives. Most of the audience doesn't know you yet, and for a good chunk of them, this five minutes is the entire dataset they'll use to decide what kind of manager you are.
It's worth naming that plainly, because pretending it's "just a presentation" makes people over-prepare the content and under-prepare the delivery. The content is usually the easy part, an update, a milestone, an introduction to your team's work. What actually goes wrong is nerves showing up as speed, hedging, or an apology for being new, none of which have anything to do with whether the update itself was good.
In a team meeting, someone will ask a clarifying question if you lose them, and a slip gets forgotten by lunch. In an all-hands, nobody interrupts, so unclear stays unclear, and because most of the room doesn't have other data points on you yet, whatever you show them carries more weight than it would with people who already know your work.
"Hi everyone, I'm [Name], I lead [team/area]. Today I want to share [one thing], why it matters, and what's next." Four sentences. Say it, then move into the content. No preamble, no apology, no "sorry, is this working" for longer than it takes to fix it.
One more thing worth planning for: the Q&A, if there is one, is a bigger part of how you're read than the prepared portion. A confident "I don't know, let me find out and follow up" lands better than a stretched answer to a question you weren't ready for. Nobody in that room expects you to have every number memorized in week one.