The tricky part is that "no hub" usually means you're still relying on something to coordinate - whether that's Alexa acting as a hub (which it can do for compatible devices), your phone, or cloud services. With your specific mix, Alexa can actually pull some of this together since it works with Hue and most smart switches, but Nest tends to operate pretty independently through Google's ecosystem. You'll get the smoothest experience consolidating everything through one platform, which for your setup probably means either going all-in on Google Home (moving Hue and switches there too) or accepting that Nest stays separate and using Alexa for the rest. A dedicated hub like SmartThings would genuinely solve this, but if you want to avoid buying more hardware, testing whether Alexa routines can at least trigger Hue scenes together is your quickest workaround.