Based on the limited guides we have on this site for this Chromebook, and a picture of a replacement keyboard on another site, (link here) I would assume that the keyboard is held in with screws around the edge of the keyboard.
These Chromebooks aren't very difficult to disassemble, so removing the guts from your current machine shouldn't be too difficult. Once the motherboard, battery, and possibly the speakers are removed, you can begin looking to see if the keyboard is held in with screws. If it is, you're in luck! Just buy a new keyboard. If it's those little plastic pop rivets, I'm sure you can make do with either remelting a little plastic on each point, or using a little glue. Good luck with the repair!