NixOs is built on Linux kernel, Fushia is built on a new (micro-ish) kernel called zircon, they are not interchangable.
They are working on some components/layer to run things from Linux, but you would not expect all things built to work directly or as well as thing designed from the get-go for Fushia in mind.
They are working on some components/layer to run things from Linux, but you would not expect all things built to work directly or as well as thing designed from the get-go for Fushia in mind.