Try this trick to add up your nick in place of AM and PM beside time. Its simple.

Method:

Step 1. Navigate to -> Start -> Control Panel -> Regional And Language Option -> Click on Customize -> Go to TIME Tab -> Change AM symbol and PM symbol from AM and PM to your name -> Apply -> OK.
Did it change? If not, follow Step 2 below.

Step 2. Now go to time in taskbar and Double Click it to open "Date and Time Property". Look place where time changes in Digital form for example, 12:22:12 AM, click to arrow to change the AM or PM by selecting and press arrow. It will show your name or name that was entered by you, Apply -> OK and be happy