You don't give yourself a nickname. It's for your team mates to decide it. which is usally your name in short. And I agree with the guy above.
Thug, Dirt, Lowlife etc, any person good at hitting other players doesn't deserve a good nickname. EDIT: Klik - I don't think the asker means -- a good hard hitting tackler but a player good at punching opponents. If I'm wrong then its a badly worded question.
Simmo Chaff Ty Blight Bludge Suri Shen Blaze Blade Glade
Spanky
Obviously Charlie and his 'likers' don't realise that by hitting you mean tackling. Ignorance is bliss. Your team will give you your nick name for better or worse.
Messhimup Messam Smithy the smiter ie anyone of the 3 ABs can't think of anymore at the mo
Nasty Nate (only works if his first name is nate) Rocksteady Flounder Defeated Upstate Bull Strut Hightower Chicken Little Gump Stealth Jaber CD Shaf Big Hit Stick Milhouse Slim Webs Ninja Suga Shy Guy Luigi Snuggles B-Hoff T-Rent Tiger DMC Ralphie