Yes, it is possible to withdraw 100 USDT via BNB chain if you deposit 100 USDT via TRC20. However, you should make sure that the CEX you are using supports this type of withdrawal. For example, if you are using FTX as your CEX, you should check to see if they support this type of withdrawal. Additionally, you should make sure that the withdrawal fees are low and that the withdrawal process is secure. Finally, you should also check to make sure that the withdrawal process is fast and efficient so that you can get your funds quickly.