What is a natural way to settle my nerves before delivering a large presentation?

Name: Shravan Date of Birth: 22 August 1995 Place of Birth: Bengaluru Time: 09:10 AM. I have an important presentation at work soon and my stress is already in full spin. I sweat, my mind goes a mile a minute, and my chest tightens up just thinking about talking in public. I have attempted deep breathing and visualization but they aren't always reliable. I don't want to use medication or beta blockers but I need something immediate and effective. Are there any natural methods such as herbal supplements, calming teas, or breathing exercises which I can use an hour before the presentation and be more relaxed and less nervous? I need to be able to talk loudly and remain calm without the feeling that I am fighting my own body.