如果你真的需要这样做（请参阅@YeasinSheikh的评论），你需要确保这些全局键在你的应用程序中是唯一的。要做到这一点，你可以在你的MyHomePage的每个示例中添加一个GlobalKey，并将这个键与你用于Chip小部件的键结合使用。
试试这个代码：

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(key: GlobalKey(), title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  // add a required Key param to the constructor and pass it to super
  const MyHomePage({required Key key, required this.title}): super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final ScrollController _chipsScrollController = ScrollController();
  String _currentChip = 'Chip 1';
  static const _chips = [
    'Chip 1',
    'Chip 2',
    'Chip 3',
    'Chip 4',
    'Chip 5',
    'Chip 6',
    'Chip 7',
    'Chip 8',
    'Chip 9',
    'Chip 10',
    'Chip 11',
    'Chip 12',
    'Chip 13',
    'Chip 14',
    'Chip 15',
    'Chip 16',
    'Chip 18',
    'Chip 19',
    'Chip 20',
    'Chip 21',
    'Chip 22',
    'Chip 23',
    'Chip 24',     
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: SizedBox(
          height: 70,
          child: ListView.separated(
            controller: _chipsScrollController,
            physics: const ClampingScrollPhysics(),
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
            scrollDirection: Axis.horizontal,
            itemCount: _chips.length,
            itemBuilder: (final BuildContext context, final int index) {
              return ChoiceChip(
                  // key now will be globally unique 
                  key: GlobalObjectKey('${widget.key}_${_chips[index]}'),
                  label: Text(_chips[index]),
                  selected: _chips[index] == _currentChip,
                  onSelected: (final bool value) {
                    _currentChip = _chips[index];
                    Scrollable.ensureVisible(
                      GlobalObjectKey('${widget.key}_${_chips[index]}').currentContext!,
                      alignment: 0.5,
                    );
                  });
            },
            separatorBuilder: (final BuildContext context, final int index) =>
                const SizedBox(width: 12),
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => Navigator.pushReplacement(
          context,
          MaterialPageRoute(
            builder: (_) => MyHomePage(key: GlobalKey(),
              title: 'Flutter Demo Home Page',
            ),
          ),
        ),
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}