diff --git a/extensions/nicknames/src/AddNicknameValidation.php b/extensions/nicknames/src/AddNicknameValidation.php
index a594eb6b4..f5fff814f 100644
--- a/extensions/nicknames/src/AddNicknameValidation.php
+++ b/extensions/nicknames/src/AddNicknameValidation.php
@@ -21,20 +21,25 @@ class AddNicknameValidation
 
     public function __invoke($flarumValidator, Validator $validator)
     {
-        $unique_nickname = ($this->settings->get('flarum-nicknames.unique')) ? 'unique:users,nickname' : '';
+        $nicknameRules = [
+            function ($attribute, $value, $fail) {
+                $regex = $this->settings->get('flarum-nicknames.regex');
+                if ($regex && !preg_match_all("/$regex/", $value)) {
+                    $fail(app('translator')->trans('flarum-nicknames.api.invalid_nickname_message'));
+                }
+            },
+            'min:' . $this->settings->get('flarum-nicknames.min'),
+            'max:' . $this->settings->get('flarum-nicknames.max'),
+            'nullable'
+        ];
+
+        if ($this->settings->get('flarum-nicknames.unique')) {
+            $nicknameRules[] = 'unique:users,username';
+            $nicknameRules[] = 'unique:users,nickname';
+        }
 
         $validator->setRules([
-                'nickname' => [
-                    $unique_nickname,
-                    function ($attribute, $value, $fail) {
-                        $regex = $this->settings->get('flarum-nicknames.regex');
-                        if ($regex && !preg_match_all("/$regex/", $value)) {
-                            $fail(app('translator')->trans('flarum-nicknames.api.invalid_nickname_message'));
-                        }
-                    },
-                    'min:' . $this->settings->get('flarum-nicknames.min', 1),
-                    'max:' . $this->settings->get('flarum-nicknames.max', 150),
-                ],
+                'nickname' => $nicknameRules,
             ] + $validator->getRules());
     }
 }
diff --git a/extensions/nicknames/src/SaveNicknameToDatabase.php b/extensions/nicknames/src/SaveNicknameToDatabase.php
index 0b5bce8b4..0fe7e0f2c 100644
--- a/extensions/nicknames/src/SaveNicknameToDatabase.php
+++ b/extensions/nicknames/src/SaveNicknameToDatabase.php
@@ -21,7 +21,18 @@ class SaveNicknameToDatabase {
             } else {
                 $actor->assertCan('edit', $user);
             }
-            $user->nickname = $attributes['nickname'];
+
+            $nickname = $attributes['nickname'];
+
+            // If unique validation is enabled, the nickname will be checked
+            // against ALL nicknames and usernames, including the username
+            // of the current user. So, to allow users to reset their nickname
+            // back to their username, in this case we'd set it to null.
+            if ($user->username === $nickname) {
+                $user->nickname = null;
+            } else {
+                $user->nickname = $nickname;
+            }
         }
     }
 }