Binance Coin is the cryptocurrency issued by the Binance exchange and trades with the BNB symbol. BNB was initially based on the Ethereum network but is now the native currency of Binance's own blockchain, the Binance chain.
BNB Chain is a blockchain created by Binance (BNB 0.07%), the world's largest cryptocurrency exchange by trading volume. The blockchain is fueled by BNB, formerly known as Binance coin. It's a decentralized, open-source ecosystem that helps users create, store, and exchange data.