I get this type of error when I write any iteration statements. the NavigationView and scrollview braces are closed below.
The error message should be self explanatory?
In SwiftUI, you can not just write arbitrary code, when a View is expected.
Remember that you are declaring a UI.
Try replacing your "for" loop with this SwiftUI code:
ForEach(cities, id: \.self) { city in
Text("City: \(city)")
}