diff --git a/packages/react-native/Libraries/AppDelegate/RCTAppDelegate.h b/packages/react-native/Libraries/AppDelegate/RCTAppDelegate.h
index e0edbef47a2..dd234fb7b16 100644
--- a/packages/react-native/Libraries/AppDelegate/RCTAppDelegate.h
+++ b/packages/react-native/Libraries/AppDelegate/RCTAppDelegate.h
@@ -158,7 +158,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (BOOL)bridgelessEnabled;
 
 /// Return the bundle URL for the main bundle.
-- (NSURL *)bundleURL;
+- (NSURL *__nullable)bundleURL;
 
 @end
 
diff --git a/packages/react-native/React/Base/RCTBridgeDelegate.h b/packages/react-native/React/Base/RCTBridgeDelegate.h
index 0d9ec0a2b13..1bc3723ea9e 100644
--- a/packages/react-native/React/Base/RCTBridgeDelegate.h
+++ b/packages/react-native/React/Base/RCTBridgeDelegate.h
@@ -20,7 +20,7 @@ NS_ASSUME_NONNULL_BEGIN
  * When running from a locally bundled JS file, this should be a `file://` url
  * pointing to a path inside the app resources, e.g. `file://.../main.jsbundle`.
  */
-- (NSURL *)sourceURLForBridge:(RCTBridge *)bridge;
+- (NSURL *__nullable)sourceURLForBridge:(RCTBridge *)bridge;
 
 @optional
 
diff --git a/packages/react-native/React/Base/RCTBundleURLProvider.h b/packages/react-native/React/Base/RCTBundleURLProvider.h
index bd627816167..3c96903ee76 100644
--- a/packages/react-native/React/Base/RCTBundleURLProvider.h
+++ b/packages/react-native/React/Base/RCTBundleURLProvider.h
@@ -9,7 +9,7 @@
 
 #import "RCTDefines.h"
 
-RCT_EXTERN NSString *const RCTBundleURLProviderUpdatedNotification;
+RCT_EXTERN NSString *_Nonnull const RCTBundleURLProviderUpdatedNotification;
 RCT_EXTERN const NSUInteger kRCTBundleURLProviderDefaultPort;
 
 #if RCT_DEV_MENU | RCT_PACKAGER_LOADING_FUNCTIONALITY
@@ -22,6 +22,8 @@ RCT_EXTERN const NSUInteger kRCTBundleURLProviderDefaultPort;
 RCT_EXTERN void RCTBundleURLProviderAllowPackagerServerAccess(BOOL allowed);
 #endif
 
+NS_ASSUME_NONNULL_BEGIN
+
 @interface RCTBundleURLProvider : NSObject
 
 /**
@@ -52,52 +54,53 @@ RCT_EXTERN void RCTBundleURLProviderAllowPackagerServerAccess(BOOL allowed);
  * The port is optional, if not specified, kRCTBundleURLProviderDefaultPort will be used
  * The scheme is also optional, if not specified, a default http protocol will be used
  */
-+ (BOOL)isPackagerRunning:(NSString *)hostPort scheme:(NSString *)scheme;
++ (BOOL)isPackagerRunning:(NSString *)hostPort scheme:(NSString *__nullable)scheme;
 
 /**
  * Returns the jsBundleURL for a given bundle entrypoint and
  * the fallback offline JS bundle if the packager is not running.
  */
-- (NSURL *)jsBundleURLForBundleRoot:(NSString *)bundleRoot fallbackURLProvider:(NSURL * (^)(void))fallbackURLProvider;
+- (NSURL *__nullable)jsBundleURLForBundleRoot:(NSString *)bundleRoot
+                          fallbackURLProvider:(NSURL *__nullable (^)(void))fallbackURLProvider;
 
 /**
  * Returns the jsBundleURL for a given split bundle entrypoint in development
  */
-- (NSURL *)jsBundleURLForSplitBundleRoot:(NSString *)bundleRoot;
+- (NSURL *__nullable)jsBundleURLForSplitBundleRoot:(NSString *)bundleRoot;
 
 /**
  * Returns the jsBundleURL for a given bundle entrypoint and
  * the fallback offline JS bundle if the packager is not running.
  * if extension is nil, "jsbundle" will be used.
  */
-- (NSURL *)jsBundleURLForBundleRoot:(NSString *)bundleRoot fallbackExtension:(NSString *)extension;
+- (NSURL *__nullable)jsBundleURLForBundleRoot:(NSString *)bundleRoot fallbackExtension:(NSString *__nullable)extension;
 
 /**
  * Returns the jsBundleURL for a given bundle entrypoint and
  * the fallback offline JS bundle if the packager is not running.
  */
-- (NSURL *)jsBundleURLForBundleRoot:(NSString *)bundleRoot;
+- (NSURL *__nullable)jsBundleURLForBundleRoot:(NSString *)bundleRoot;
 
 /**
  * Returns the jsBundleURL for a given bundle entrypoint and
  * the fallback offline JS bundle. If extension is nil,
  * "jsbundle" will be used.
  */
-- (NSURL *)jsBundleURLForFallbackExtension:(NSString *)extension;
+- (NSURL *__nullable)jsBundleURLForFallbackExtension:(NSString *__nullable)extension;
 
 /**
  * Returns the resourceURL for a given bundle entrypoint and
  * the fallback offline resource file if the packager is not running.
  */
-- (NSURL *)resourceURLForResourceRoot:(NSString *)root
-                         resourceName:(NSString *)name
-                    resourceExtension:(NSString *)extension
-                        offlineBundle:(NSBundle *)offlineBundle;
+- (NSURL *__nullable)resourceURLForResourceRoot:(NSString *)root
+                                   resourceName:(NSString *)name
+                              resourceExtension:(NSString *)extension
+                                  offlineBundle:(NSBundle *)offlineBundle;
 
 /**
  * The IP address or hostname of the packager.
  */
-@property (nonatomic, copy) NSString *jsLocation;
+@property (nonatomic, copy, nullable) NSString *jsLocation;
 
 @property (nonatomic, assign) BOOL enableMinification;
 @property (nonatomic, assign) BOOL enableDev;
@@ -124,20 +127,20 @@ RCT_EXTERN void RCTBundleURLProviderAllowPackagerServerAccess(BOOL allowed);
  * - runModule: When true, will run the main module after defining all modules. This is used in the main bundle but not
  *     in split bundles.
  */
-+ (NSURL *)jsBundleURLForBundleRoot:(NSString *)bundleRoot
-                       packagerHost:(NSString *)packagerHost
-                          enableDev:(BOOL)enableDev
-                 enableMinification:(BOOL)enableMinification
-                    inlineSourceMap:(BOOL)inlineSourceMap;
++ (NSURL *__nullable)jsBundleURLForBundleRoot:(NSString *)bundleRoot
+                                 packagerHost:(NSString *)packagerHost
+                                    enableDev:(BOOL)enableDev
+                           enableMinification:(BOOL)enableMinification
+                              inlineSourceMap:(BOOL)inlineSourceMap;
 
-+ (NSURL *)jsBundleURLForBundleRoot:(NSString *)bundleRoot
-                       packagerHost:(NSString *)packagerHost
-                     packagerScheme:(NSString *)scheme
-                          enableDev:(BOOL)enableDev
-                 enableMinification:(BOOL)enableMinification
-                    inlineSourceMap:(BOOL)inlineSourceMap
-                        modulesOnly:(BOOL)modulesOnly
-                          runModule:(BOOL)runModule;
++ (NSURL *__nullable)jsBundleURLForBundleRoot:(NSString *)bundleRoot
+                                 packagerHost:(NSString *)packagerHost
+                               packagerScheme:(NSString *__nullable)scheme
+                                    enableDev:(BOOL)enableDev
+                           enableMinification:(BOOL)enableMinification
+                              inlineSourceMap:(BOOL)inlineSourceMap
+                                  modulesOnly:(BOOL)modulesOnly
+                                    runModule:(BOOL)runModule;
 /**
  * Given a hostname for the packager and a resource path (including "/"), return the URL to the resource.
  * In general, please use the instance method to decide if the packager is running and fallback to the pre-packaged
@@ -145,8 +148,8 @@ RCT_EXTERN void RCTBundleURLProviderAllowPackagerServerAccess(BOOL allowed);
  */
 + (NSURL *)resourceURLForResourcePath:(NSString *)path
                          packagerHost:(NSString *)packagerHost
-                               scheme:(NSString *)scheme
-                                query:(NSString *)query
+                               scheme:(NSString *__nullable)scheme
+                                query:(NSString *__nullable)query
     __deprecated_msg("Use version with queryItems parameter instead");
 
 /**
@@ -157,6 +160,8 @@ RCT_EXTERN void RCTBundleURLProviderAllowPackagerServerAccess(BOOL allowed);
 + (NSURL *)resourceURLForResourcePath:(NSString *)path
                          packagerHost:(NSString *)packagerHost
                                scheme:(NSString *)scheme
-                           queryItems:(NSArray<NSURLQueryItem *> *)queryItems;
+                           queryItems:(NSArray<NSURLQueryItem *> *__nullable)queryItems;
 
 @end
+
+NS_ASSUME_NONNULL_END