FileZilla does not support any kind of import from other applications.
Writing a script to convert WinSCP INI configuration file to FileZilla XML configuration file should not be that difficult. If it's worth the effort, depends on how many sessions you have. Converting passwords encrypted by WinSCP to an unencrypted (or base64-encoded) form that FileZilla uses would be the most challenging (if you save passwords).
Note, that once you realize that WinSCP is better and you decide to switch back, you can easily import your new FileZilla sessions to WinSCP:
https://winscp.net/eng/docs/ui_import