The first video released shows cops aggressively going after him, pulling him out of his car, cursing, etc...
No one has described what happened before that interaction.
I have read various rumors from street drag-racing, to drug deals, to Nichols ramming a cop-car, to the girlfriend story.
Perhaps the cops were chasing him to intimidate, and. fearing for his safety, he went Ben Hur on their car. I really would like to see the dash-cam video.
The cops claimed reckless driving. After his murder, an investigation revealed no evidence of reckless driving. NONE.