There are 2 ways you can import OATH hardware OTP tokens into OKTA:

Use OKTA's API

Use SafeID Token Service

SafeID Token Service (STS) is a product/service that we have developed for customers who need to manage a large quantity of SafeID tokens with Azure AD and/or OKTA. 

SafeID Token Service provides a Web-based GUI console that allows customers to manage the full life cycle of the SafeID token by simply pointing and clicking. You can assign, activate, deactivate, unassign, delete and replace a token, etc with one single click.

For more details, click SafeID Token Service