Fighter gets nut shotted, waits for ref to step in and gets knocked out. Ref shouldve stepped in, but at the same time, fighter needs to defend himself at all times…tricky 
Cant tell if it was a nut shot cause the guy with the camera was more interested in filming a post rather than moving. From the sound it sounded like every other inside leg kick. The refs job is not to stop the fight if a fighter asks for the fight to be stopped but rather by what the ref sees. I will give the benifit of the doubt to the ref in this one.
protect yourself at all times, thats the fighters responsibility.