ESPN is writing a series of posts on the best NFC North players, and Green Bay Packers NT B.J. Raji is mentioned for having the best nickname:

After participating in a jumbo offensive package at the goal line, Raji began calling himself "The Freezer." As NFC North fans remember, William "The Refrigerator" Perry rose to cult status in a similar role 25 years ago. 

I heard this nickname last year, but I wasn't sure it would stick. Apparently it still has some life to it.