This is a example to interate over nested list and access map inside it and render values on it.

nested_list_iteration.dart

import 'dart:convert';

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  var questions = [
    {
      'question': '1+1',
      'answer': [
        {'text': 2,'correct':1},
        {'text': 3,'correct':0},
        {'text': 4,'correct':0},
        {'text': 5,'correct':0}
      ]
    },
    {
      'question': '1+2',
      'answer': [
        {'text': 2,'correct':0},
        {'text': 3,'correct':1},
        {'text': 4,'correct':0},
        {'text': 5,'correct':0}
      ]
    },
    {
      'question': '1+3',
      'answer': [
        {'text': 2,'correct':0},
        {'text': 3,'correct':0},
        {'text': 4,'correct':1},
        {'text': 5,'correct':0}
      ]
    },
    {
      'question': '1+4',
      'answer': [
        {'text': 2,'correct':0},
        {'text': 3,'correct':0},
        {'text': 4,'correct':0},
        {'text': 5,'correct':1}
      ]
    },
    {
      'question': '1+6',
      'answer': [
        {'text': 7,'correct':1},
        {'text': 8,'correct':0},
        {'text': 9,'correct':0},
        {'text': 10,'correct':0}
      ]
    },
    {
      'question': '1+6',
      'answer': [
        {'text': 7,'correct':1},
        {'text': 8,'correct':0},
        {'text': 9,'correct':0},
        {'text': 10,'correct':0}
      ]
    },    {
      'question': '1+7',
      'answer': [
        {'text': 7,'correct':0},
        {'text': 8,'correct':1},
        {'text': 9,'correct':0},
        {'text': 10,'correct':0}
      ]
    },
  ];
  
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: questions.length,
      itemBuilder: (BuildContext context, int index) {
        final quest = questions[index]['answer'];
        return Row(
          children: [
            for (final q in quest)
              RaisedButton(
                onPressed: (){
                  print(q["correct"] == 1);
                },
                child: Text(q["text"].toString() ?? ""),
              )
          ],
        );
      }
    );
  }
}