[Vuejs]-How to trigger specific action after event on all opened tabs in Nuxt.js

what about socket.io ? have you read about it ?
i think you could achive your desire performance with it

In this case the solution could be: use POST request in nuxt proxy server or in your backend, like axios.post('/data', payload) and connect the websockets, you can use pusher for that. The final logic is: user add some data => post to server => server emits the websockets event => vuex listen to the event and the data will be reactive in all tabs.