Thirteen people were taken to hospital after the incident on Sunday at the Streets venue in Porthcawl.
The Independent Police Complaints Commission said it had received a referral from South Wales Police
A 24-year-old man is due to appear at Cardiff Crown Court on 9 November charged with a number of offences.
Jan Williams, the IPCC Commissioner for Wales, said: "A police van was in the vicinity shortly prior to the collision and our independent investigation will examine what police action was taken in respect of the Audi, and whether relevant procedures were followed."
The watchdog said police had passed a mandatory referral to them immediately after the incident on John Street.
The body is appealing for anyone who may have seen the white police van and any interactions with the Audi A4 car in or around the area prior to the crash to come forward.
A police watchdog has launched an investigation into how police may have been involved prior to a crash outside a Bridgend county nightclub.