Thanks for posting here in the Google Nest Community.
I know how it feels when something isn’t working as it should, so let’s get this resolved. A few things: what's the LED light status (solid or flashing white)? What's the distance between the router and your Chromecast device? What messages does the TV display? Does it display Set me up?
Make sure that both Bluetooth and location services are on. If you are using an iOS device check if Local Network Access is enabled. Check the steps below,
Check this helpful link too for more steps.
Keep me posted.