VULNERABILITY DETAILS
Chrome saved autofill username and password is unexpectedly/unwantedly injected into an HTML form when the username is exactly the string "Nick".

I have tested and reproduced this behavior on two different computers and user accounts on an edit account form on a website. The HTML form does not contain any HTML autocomplete attributes or any non-standard behavior.

<input type="text" name="f[username]" value="Nick" placeholder="Enter username" id="f_username">
<input type="password" name="f[password]" placeholder="(unchanged)" id="f_password">

In more detail: I login with my own credentials to a CMS backend for a website that manages multiple user accounts. I edit a user page which contains HTML username and password fields for that user (not myself), but my own saved Chrome autofill data gets injected into the form fields --- but only if the username is Nick! Not Nicky, not Nickie, not any other string, just "Nick".

Is this an Easter egg? Do you have a developer who's coded in his own name for testing purposes and forgotten it? In any case, this can compromise saved username and password data in Chrome or lead to compromising user mistakes.

VERSION
Chrome version: 69.0.3497.92
Operating System: Windows 10 latest up-to-date (15th Sep 2018)

REPRODUCTION CASE
Unfortunately I cannot attach an HTML file as this requires authenticating to a website with saved Chrome credentials and then accessing an HTML form where the existing username field value is "Nick". It will be easier for you to reproduce on an existing system of your choice.

FOR CRASHES, PLEASE INCLUDE THE FOLLOWING ADDITIONAL INFORMATION
Type of crash: n/a
Crash State: n/a
Client ID (if relevant): n/a