SwiftUI preview looks different from the simulator

Question

Can anybody tell me why my views looks fine in the preview, but get pushed down in the simulator? It's super simple and very little code so I honestly have no idea what's going on. Here is my code:

import SwiftUI
import FirebaseAuth

struct MainView: View {
   @EnvironmentObject var viewModel: AppViewModel
   
   var body: some View {
      NavigationView {
         List {
            ForEach(0..<10) { _ in
               Text("Views go here")
               Text("Something else to track")
            } //: LOOP
            
         } //: LIST
         .navigationTitle("Track Stuff")
         .navigationBarItems(
            trailing: Button(action: {viewModel.signOut()}) {
               Text("Sign out")
                  .foregroundColor(buttonColor)
            }
         )
      } //: NAVIGATION
      .navigationViewStyle(StackNavigationViewStyle())
   }
}

struct MainView_Previews: PreviewProvider {
   static var previews: some View {
      MainView()
   }
}

Answer 1

As mentioned by Andrew in comments, the problem arose because I had nested NavigationViews.