AssetBundleLoader.cs

using UnityEditor;
using UnityEngine;

public sealed class AssetBundleLoader : ScriptableWizard
{
    public string sourcePath;

    [MenuItem("Wizard/Load Asset Bundle")]
    private static void CreateWizard()
    {
        DisplayWizard<AssetBundleLoader>("Load Asset Bundle", "Load");
    }

    protected override bool DrawWizardGUI()
    {
        bool modified = base.DrawWizardGUI();

        if (GUILayout.Button("Browse..."))
        {
            string value = EditorUtility.OpenFilePanel("Load asset bundle", "", "*");
            if (sourcePath != value)
            {
                sourcePath = value;
                modified = true;
            }
        }

        return modified;
    }

    private void OnWizardCreate()
    {
        var assetBundle = AssetBundle.LoadFromFile(sourcePath);
        foreach (GameObject gameObject in assetBundle.LoadAllAssets())
            Instantiate(gameObject);
    }
}