Assuming your audience are beginners (as it is an intro talk), I find it immensely useful when tech talks have slides that follow this kind of pattern:
- Problem/Feature/Reason why it's useful
- Code
- Demo of the problem/feature/reason working (whether recorded or live)
Doing a bunch of live demos is real risky for a first tech talk, but if you practice (I mean really practice, with network access turned off for example), and know your stuff, it's possible.
If you're game to do a demo, I think one of the most important things you can demo is going 0-100 with a small kotlin app on Android. This will require you to make some choices that your audience would normally make themselves (like how to develop the app, not everyone uses android studio), but if Kotlin for Android Development is actually valuable, it should be self-evident from watching it used (you may have to throw in some problems that you solve by writing idiomatic Kotlin, and explain why they would look worse in Java or whatever else).
Also you might want to include these slides (probably just one so people don't lose focus):
- Options for native android development (to set up the next slide), you might briefly explain things like React Native, Go for android, Java, Scala, Clojure. Hard to keep this to one slide but it is valuable because it makes the person watching feel like they know the landscape, at least at a high level, and motivates the talk.
- What/Who/When/Why for Kotlin on Android
Here's an excellent talk that came to my mind:
https://www.youtube.com/watch?v=0GzzFeS5cMc