TIBCO Nimbus has two versions which may seem similar in terms of build numbers.   V 10.2.0 and V 10.2.2 
What is the difference between these two versions?

What is the difference between TIBCO Nimbus V 10.2.0 and V 10.2.2

TIBCO Nimbus V 10.2.2 was released primarily for usage within the TIBCO Nimbus Cloud Service.
The only difference between this and V 10.2.0 is the below functionality
We would therefore recommend that an on premise customer upgrades to V 10.2.0 or to V 10.3 which has recently been released. 
(Please ensure you check for hotfixes via https://support.tibco.com to ensure you install the latest version)
:

Bulk User Management
A solution has been provided for the bulk user import and management of
a customer's instance on the Nimbus Cloud environment. Provision for this is
through a bulk user API with five possible actions:
1. Returns a list of matching user accounts based on the filter and
pagination settings provided.
2. Creates a new user if one does not already exist.
3. Updates existing user accounts.
4. Removes existing users completely.
5. Returns a specific user account.
This addresses bulk user management by way of a REST API, existing user
workflows and Nimbus functionality will be unchanged.

Further information can be found in the Bulk User Management API Guide
following this link: docs.tibco.com/products/tibco-nimbus.