diff --git a/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h b/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h
index ddbb87aa62e14..e71b078524a36 100644
--- a/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h
+++ b/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h
@@ -15,6 +15,8 @@
 #include "FlutterPlugin.h"
 #include "FlutterTexture.h"
 
+NS_ASSUME_NONNULL_BEGIN
+
 @class FlutterEngine;
 
 /**
@@ -55,8 +57,8 @@ FLUTTER_EXPORT
  * @param nibBundleOrNil The NIB bundle.
  */
 - (instancetype)initWithEngine:(FlutterEngine*)engine
-                       nibName:(NSString*)nibNameOrNil
-                        bundle:(NSBundle*)nibBundleOrNil NS_DESIGNATED_INITIALIZER;
+                       nibName:(nullable NSString*)nibName
+                        bundle:(nullable NSBundle*)nibBundle NS_DESIGNATED_INITIALIZER;
 
 /**
  * Initializes a new FlutterViewController and `FlutterEngine` with the specified
@@ -66,9 +68,9 @@ FLUTTER_EXPORT
  * @param nibNameOrNil The NIB name to initialize this UIViewController with.
  * @param nibBundleOrNil The NIB bundle.
  */
-- (instancetype)initWithProject:(FlutterDartProject*)projectOrNil
-                        nibName:(NSString*)nibNameOrNil
-                         bundle:(NSBundle*)nibBundleOrNil NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithProject:(nullable FlutterDartProject*)project
+                        nibName:(nullable NSString*)nibName
+                         bundle:(nullable NSBundle*)nibBundle NS_DESIGNATED_INITIALIZER;
 
 - (void)handleStatusBarTouches:(UIEvent*)event;
 
@@ -184,4 +186,6 @@ FLUTTER_EXPORT
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 #endif  // FLUTTER_FLUTTERVIEWCONTROLLER_H_
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
index 87e605e97fd48..7e00737db8ead 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
@@ -71,10 +71,10 @@ @implementation FlutterViewController {
 #pragma mark - Manage and override all designated initializers
 
 - (instancetype)initWithEngine:(FlutterEngine*)engine
-                       nibName:(NSString*)nibNameOrNil
-                        bundle:(NSBundle*)nibBundleOrNil {
+                       nibName:(nullable NSString*)nibName
+                        bundle:(nullable NSBundle*)nibBundle {
   NSAssert(engine != nil, @"Engine is required");
-  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
+  self = [super initWithNibName:nibName bundle:nibBundle];
   if (self) {
     _viewOpaque = YES;
     _engine.reset([engine retain]);
@@ -90,15 +90,15 @@ - (instancetype)initWithEngine:(FlutterEngine*)engine
   return self;
 }
 
-- (instancetype)initWithProject:(FlutterDartProject*)projectOrNil
-                        nibName:(NSString*)nibNameOrNil
-                         bundle:(NSBundle*)nibBundleOrNil {
-  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
+- (instancetype)initWithProject:(nullable FlutterDartProject*)project
+                        nibName:(nullable NSString*)nibName
+                         bundle:(nullable NSBundle*)nibBundle {
+  self = [super initWithNibName:nibName bundle:nibBundle];
   if (self) {
     _viewOpaque = YES;
     _weakFactory = std::make_unique<fml::WeakPtrFactory<FlutterViewController>>(self);
     _engine.reset([[FlutterEngine alloc] initWithName:@"io.flutter"
-                                              project:projectOrNil
+                                              project:project
                                allowHeadlessExecution:NO]);
     _flutterView.reset([[FlutterView alloc] initWithDelegate:_engine opaque:self.isViewOpaque]);
     [_engine.get() createShell:nil libraryURI:nil];