migration – Using the Migrate Plus API to select elements in a JSON array

I am new to Drupal, I need to solve the following error in my migration import.

For example, nest:

[
    {
       nid: [
           {
             value: "110538"
           }
       ],
uuid: [
           {
             value: "a90278c4-8bac-4539-b0c7-a6f62ed11975"
           }
       ],
vid: [
          {
            value: "110595"
          }
       ]
    }
]

What kind of field selector is needed to get nest value?

I have the following migrations:

source:
plugin: url
data_fetcher_plugin: http
data_parser_plugin: json
URL: https://example.com/rest/article
login:
nest:
type: whole
item_selector: /
the fields:
-
name: nest
label: 'Nest'
selector: nest
-
name: title
label: 'Title & # 39;
selector: / title
constants:
source_base_path: https: //example.com/'
process:
nest: nest
title: title
type:
plugin: default_value
default_value: & # 39; article & # 39;
destination:
plugin: "entity: node"
dependencies_migration: null

when i try to run the migration import, the following error has occurred:

 [warning]    array_flip (): Can only reverse the values ​​STRING and INTEGER! EntityStorageBase.php: 264
 [warning] Illegal offset type ContentEntityStorageBase.php: 955
 [warning] Type of illegal offset in isset or empty EntityStorageBase.php: 250

In Connection.php, line 729:

Placeholders must have an end [] if they must be extended with an array of values. 

I need help to solve this error.