I'm probably not the best person to ask, since the last time I touched Powershell, it was Windows only, but I'd say nushell is likely a lot more platform-agnostic, has sane syntax and follows a functional paradigm. Plugins are written in Rust. It's probably not worth it if all you do is Windows sysadmin work, as you'd have to serialize and deserialize data when interacting with Powershell from nu.
Last I looked, powershell's startup time on linux was disappointing. Understandable to an extent given it was bootstrapping a bunch of dotNET stuff that would already be there on windows.
But slow enough that I couldn't use or recommend it to my team.
On the surface, it looks like I'd be giving up the decently sized ecosystem of Powershell libraries for a new ecosystem without much support?
I'm interested in knowing what Nushell does differently since I'm wanting to find a better shell.