Caseta already works with the Nest Home/Away Assist feature. You need to first set up Home/Away Assist in the Nest app, then add your Nest products to the Lutron app. After that, choose the "Arriving/Leaving Home" option in the settings menu of the Lutron app and choose 'Nest Home/Away Assist' as what decides if you are home. I've been using this in my own home for a little while now and it works well.