Used to describe an event, object or person which is of little importance. Stems from the fact that chickens (at least those bred as food) have wings but can'tfly, rendering the wings unimportant. Can be used in place of a reassuring "don't worry about it" statement but often used as a sarcastic retort suggesting that which is being described is really not as important as the person saying it believes
Dave: Man I can't beleive I have to work on Saturday
Steve: Hey man, it ain't no thing but a chicken wing
OR
Dave: I got toally carved up by some d*ckhead white van at the roundabout
Steve: So? It ain't no thing but a chicken wing
Statement of the raw simplicity of a task, implying that all
it takes is hard, not necessarily intelligent, work and effort.
Made famous by Body-Builder and Youtube sensation Ronnie Coleman
Coleman, whilst attempting to lift 800 pounds with his legs:
Ain'tnothing to it but to do it!