Accessing nested private static class in Java

I have following public class in Java which looks like:

public class MyClass 
{

  private static class MyNestedClass<T> extends SomeOtherClass
  {
  }

}

I am writing a test where I need to create a mock object for MyNestedClass class using PowerMockito, but am not able to access the class since it's private. Is there a way I can access MyNestedClass?

I tried the following:

MyClass.MyNestedClass myNestedClass = new MyClass.MyNestedClass()

and

MyClass testNoteActivity = Mockito.spy(MyClass.class);
testNoteActivity.MyNestedClass myNestedClass = new testNoteActivity.MyNestedClass()

Both didn't work for me.