Nesting gmail labels results in an unnecessarily long display that includes both parent and child labels. This will trim down the label names so you only see the child.
You can Follow the below Step By Step procedure to install the Short Gmail Labels Chrome Extension to your Chrome Web browser.
It is the Short Gmail Labels Chrome extension download link you can download and install Chrome Browser.
Set Gmail labels or Gmail filters as tabs
Press Alt+A to expand or collapse a Gmail thread
Adds Google Inbox bundles to Gmail
Set the format of the date and time for mails in your inbox as you want
Preview emails in inbox.
Now you can resize the label column in Gmail