answering my own question: this mostly naive implementation works:

haxe
@:jsRequire('@react-navigation/native','NavigationContainer')
extern class NavigationContainer extends ReactComponentOfProps<ViewProps> {}

@:jsRequire('@react-navigation/stack','createStackNavigator()')
extern class Stack extends ReactComponentOfProps<ViewProps> {}

@:native('Stack.Navigator')
extern class StackNavigator extends ReactComponentOfProps<ViewProps> {}

@:native('Stack.Screen')
extern class StackScreen extends ReactComponentOfProps<{name:String, component:Dynamic}> {}