Chickadee does not seem to be packaged for GuixSD yet: I'll work on it.
Also guile-sdl2 does not seem to work on GuixSD either: the module cannot be found. There might be an error in the package definition. I'll work on that too.
Off-topic: David, I just figured out that your blog has an atom feed at https://dthompson.us/feed.xml, but I could not find any explicit link on your website. Is it intentional?