Not Nest, but a few options for smoke detectors. 1. First Alert Z-Wave Smoke and CO detectors. I think there is a smoke only option too. I use 8 of these, they work well. 2. Existing smoke detectors and the Z-Wave listener that detects the North American smoke detector tone pattern. It hears your existing alarms and conveys it to Smartthings, works natively. 3. Wyze cameras listen for the standard Smoke and CO tone patterns of your existing/regular smoke detectors as well, but don't integrate with ST natively, have to tie it into ST via IFTTT. I use this method too, works well. Hope this is helpful to anybody.