On a 2002 Chevy S10 V6, Bank 2 Sensor 1 is located on the exhaust manifold or catalytic converter
on the passenger side (right side) of the engine. It's the upstream O2 sensor on that side. "Upstream" means it's closer to the engine than the downstream sensor (Bank 2 Sensor 2).
To be absolutely certain, you should consult a repair manual specific to your year and engine. The exact location can vary slightly depending on the specific engine configuration. A diagram in a repair manual will show you precisely where it's located.
