I was “father” owing to a part-time job I did on the weekends.
The sales manager was Tanuki (a trickster and liar in Japanese folk tales)
The web designer was The Fly.
A long time ago, we had a co-worker with a long Polish name - something like Karczmarczyk. We just called her “Eyechart”.
Not at my job, but a place I frequent daily hired a second Chris I forget his last name but it starts with a P. I heard everyone calling him Chris P. so I made the natural jump to Krispy Kreme. The whole store loved it.
He hates me.
Hears to you Krispy Kreme.
Hmm. Guess we’re a bunch of fuddy-duddies, I can’t think of anyone with any real knicknames–at least not the backstabby kind.
I do have a co-worker named Apollonio, who goes by Paulo or Polo for short. One day I called him Polo Loco, which got mutated into Pollo Loco (the crazy chicken, which is also the name of a fastfood chain). I still call him that when I’m feeling fiesty or when he’s asking for it. Somewhere along the line, I started calling him Palo Malo (bad stick), but I dropped it after a while because I was afraid it was too suggestive. But he’s a sweet, funny guy and the only person I feel comfortable giving a dumb knickname to.
Well, I do call Cynthia “Sweet Cynthia” because she wears real sweet smelling perfumes–you can tell when she’s at work because the hallways leading to her cube smell like fruit or candy or fruit-flavored candy. Yet it’s not as headachingly noxious as some other people’s perfumes, so I don’t mind. It just lets me know that Sweet Cynthia is here today 
(And, y’know, she’s a pretty nice lady, too.)
I know. I didn’t read the instructions…and then I hoped no one would notice. Thanks. 
We’ve got Chocolate Thunder, Melly Mel, Ion and the Pigfucker. Obviously, that last one is secret. My old boss and I tend to address one another by last name only, in a flippant but affectionate sort of way.