[Vuejs]-How to access to nested action in vuex store modules?

I think you might need namespaced: true on the main store as well as the producto store

export default new Vuex.Store({
  namespaced: true,
  modules: {
    ...
    producto,
    ...
  }
})

because this.$store.dispatch('producto/list/getItems') effectively has two namespaces in it.