I'm not aware of anyone running this configuration, but Okta is a valid OIDC identity provider, and FusionAuth supports OIDC compliant IdPs, so this should work.
Weirdly, I didn't find Okta documentation on setting up their service as an IdP, but I did find this Auth0 doc. I'd have to test, but it looks like you'll need to set up a FusionAuth lambda to reconcile the user data.
Hope this helps.