How to access global mixin in a nuxt plugin?

Nuxt version: 2.14.12

Helpers mixins "@/mixins/helpers.js":

export default {
  methods: {
    clickMe() {
      console.log('method fired')
    }
  }
}

Injecting mixins as plugin "~/plugins/mixins.js":

import Vue from 'vue'

import helpersMixin from '@/mixins/helpers'
Vue.mixin(helpersMixin)

Then including this plugin in nuxt.config.js:

plugins: [
  '~/plugins/mixins',
]

Then i can use a method this.clickMe() inside any Vue instance, but in a plugins i've inspected context, context.app - couldn't see info about mixin methods injected. Is it even possible?