OKTA does not provide a GUI console for importing and managing OATH hardware OTP tokens. In order to import OTP tokens, you will have to use OKTA's API. Below is the OKTA's official guide:
https://help.okta.com/en/prod/Content/Topics/Security/mfa-totp-seed.htm
https://developer.okta.com/docs/reference/api/factors/#enroll-custom-hotp-factor
On the step of Add TOTP Factor, fill in the form as below:
