Possible to use call to execute remote powershell script?

Hello,
Does anyone know if you can use the call command to execute a powershell script a remote windows host?

You can use the call command to execute any command on the remote server, that the SSH server allows you to execute, and that does not require a terminal emulation.

So yes, in general, it's possible to execute a PowerShell script.

Though note that WinSCP is not the right tool to automate command execution. The call command is just a handy feature, if you want to execute commands in addition to file transfers. If you want to automate commands only, you better use another tool, like PuTTY Plink.