postcss-nested: [object Object] is not a PostCSS plugin after upgrade to 5.0.0

I’m using postcss-nested inside Nuxt, my config that I was using before the upgrade with v.4.2.3 was working just fine nuxt.config.js

export default {
    build: {
        postcss: {
    // Allows the use of single line comments
    // in .pscss and .vue files
    parser: 'postcss-comment',
    // Add plugin names as key and arguments as value
    // Install them before as dependencies with npm or yarn
    plugins: {
      'postcss-import': {},
      tailwindcss: {},
      'postcss-nested': {},
      'postcss-hexrgba': {},
      'postcss-custom-properties': {
        importFrom: [{customProperties}]
      },
      autoprefixer: {}
    }
    }
}

but after the upgrade I started to get an error which fails the build

 ERROR  in ./fomos/droplet.vue?vue&type=style&index=0&lang=postcss&

Module build failed (from ./node_modules/postcss-loader/src/index.js):
Error: [object Object] is not a PostCSS plugin
    at Processor.normalize (H:\Projects\Kare\frontend\node_modules\postcss\lib\proc
essor.js:168:15)
    at new Processor (H:\Projects\Kare\frontend\node_modules\postcss\lib\processor.
js:52:25)
    at postcss (H:\Projects\Kare\frontend\node_modules\postcss\lib\postcss.js:55:10
)
    at H:\Projects\Kare\frontend\node_modules\postcss-loader\src\index.js:140:12
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)