First of all: Native Swift support is not supported, because Kotlin does only support Objective-C. Next, it depends on your definition of Compose 😄 If you mean Compose UI, it is a UI framework which stable version currently does not support iOS. Alpha versions of JetBrains Compose support iOS and for SwiftUI you need the wrapper:
https://developer.apple.com/tutorials/swiftui/interfacing-with-uikit. See the ios examples
https://github.com/JetBrains/compose-jb/tree/master/experimental/examples/falling-balls-mpp.
Alternatively, you can share everything but UI, so Data, Business logic, ViewModels, Networking, etc with Kotlin Multiplatform and implement your UI with Compose UI on Android/Desktop, and implement the UI for iOS using SwiftUI.
This is done in my sample
https://github.com/hfhbd/ComposeTodo or at
https://github.com/joreilly/PeopleInSpace