Here is a tip on how to reset the password for Nutanix Prism local user. The guide applies to Nutanix Prism Central as well. There are two ways.

1. Using Prism interface

Log in to Prism Element with domain user and  go to User Management

Prism user management

From the user's window choose user and click update. On the bottom of the applet there is a Reset password button.

2. Command line

Log in to CVM over SSH and get into ncli command line.

Follow the step by step instructions by reading Reset Web Console or nCLI Password

Also if you want to know how to modify the Prism user password expire days for security reasons, you can follow this article: Modify Prism admin and console user password expire days.