The Brief: "Chain" is slang for a gold or silver chain necklace.

Bluesquiggle
DEEP DIVE

“Chain” is slang for a gold or silver chain necklace. A chain is a status symbol, particularly in rap and hip hop.

Don’t look rich, I ain’t got no chain (huh) – Chance the Rapper, “No Brainer

2 chainz’s name refers to his signature two chains (or more) which he wears.

I wear every single chain, even when I’m in the house – Drake, “Started from the Bottom”