Sucks but you shouldn't have riled him up. Not like there's rules or someone in charge and it's only one person. Let him go back to his spot and try not to play sherriif next time over a phone. It'll only lead to drama.
"Shouldn't have riled him up"? Really? I think the douche line cutting was doing the riling, don't you?
What if next time he thinks, "Sod the chair, I'll just turn up and push in at the front"? Is that acceptable? How would you stop him then? I mean, the only difference is that there was a chair there or not - but this guy throwing his weight around to get his own way (unfairly) results in ultimately the same stand-off.
"He's only one guy" - yes, maybe. But next time it could be more. He might bring a friend. Other's might think "why the heck should I bother queuing and playing fair?".
Pandering to these bullies is not the way you maintain order and fairness. I'm not saying that anyone should "take the law into their own hands" - but there are clearly two options here:
1) As others have said, if he used threatening behaviour then call the cops.
2) As soon as the store opens, let the staff know what had happened. Ask them to look at CCTV footage if they so wish to backup your claim.
Just letting a bully get away with their bullying behaviour is the wrong thing to do, for everyone.... Unfortunately some bullies never grow up - doesn't mean their behaviour should be tolerated though.