I am having an issue when creating a SpriteKit scene within SwiftUI. I created this project initially as a SwiftUI project.
Her
Here's a SpriteKit container View which can be used this way:
SpriteKitContainer(sceneName: "MainScene")
struct SpriteKitContainer : UIViewRepresentable {
    let sceneName: String
    class Coordinator: NSObject {
        var scene: SKScene?
    }
    func makeCoordinator() -> Coordinator {
        return Coordinator()
    }
    func makeUIView(context: Context) -> SKView {
        let view = SKView(frame: .zero)
        view.preferredFramesPerSecond = 60
        view.showsFPS = true
        view.showsNodeCount = true
       //load SpriteKit Scene
       guard let aScene = SKScene(fileNamed: sceneName)
       else {
            view.backgroundColor = UIColor.red
            return view
       }
       aScene.scaleMode = .resizeFill
       context.coordinator.scene = aScene
       return view
    }
    func updateUIView(_ view: SKView, context: Context) {
       view.presentScene(context.coordinator.scene)
    }
}
#if DEBUG
struct ContentView_Previews : PreviewProvider {
   static var previews: some View {
      // Replace "MainScene" with your SpriteKit scene file name
      SpriteKitContainer(sceneName: "MainScene")
         .edgesIgnoringSafeArea(.all)
         .previewLayout(.sizeThatFits)
      }
}
#endif