Kotlin has everything Swift has plus some more as well as the awesome ecosystem that comes with working on the JVM whereas Swift has some catching up to do if you want to use it server-side. Await Async is coming soon under Co-routines, so for now that's one thing Swift has that Kotlin doesn't yet have.
Kotlin is using Type Inference whereas Swift is a little more flexible in this regard.
Kotlin can be used everywhere where Java is being used, so Android, Serverside, compiled to JS, etc. The Java ecosystem is still an awesome ecosystem, the language itself is just showing its age, this is where Kotlin comes to the rescue.
How complicated you want to go is up to you, use Maven, Gradle, Ant, straight Kotlin compiler, Eclipse, IntelliJ, etc. Here's a simple hello world example that gets compiled to JavaScript:
try.kotlinlang.org