Remove the BB and clean everything. Apply grease to threads and reinstall to torque spec.
Apply grease to spindle and to bearings. When you install the crank make sure there is adequate preload.
It may not be the BB. Depending on the design of the Sram crank, it maybe the crank arm attachment to the spindle if it is left leg specific.

Also, it could be your left pedal. How are the bearings in your pedals? A tick every turn can even be your saddle.

Good news is....BSA is the best and most reliable BB for clicks and creaks. I am not a fan of Sram cranks...prefer Shimano or Campy cranks with BSA...but hopefully you can quiet it down.
Make sure you use a torque wrench on the left arm attachment bolt.

Good luck