Not on spiritual matters, no, but I have taught several computer courses over the years and am comfortable speaking in front of an audience. (I can actually be serious when I force myself!)
In "spiritual" terms, I keep a
very low profile with those around me and though I am a master of "Koan speak" I would not relish speaking to a larger audience on any spiritual topic. I did the "teacher" thing once, well, twice, and vowed I would never make that mistake again.
I loved teaching in a classroom setting. That was a very rewarding experience.
I didn't actually prepare lectures but would go through concepts from stem to stern in a very methodical way. It was done on the fly and without notes. I knew my topic(s) thoroughly so I could handle any questions with ease. The tricky part was finding ways to express it to my mainly Hong Kong Chinese students who were still mastering English. That is where we had a lot of fun in back and forth discussions.
Just talk from the heart and do not get too deep, especially at first. Work out common themes that most would understand and then work them into established Buddhist doctrine. Nothing simpler
(I'm sure you will do fine.)