My nephew had the same issue I tried these tips:
Continue to have him use the bathroom before bed.
Try not giving him liquids after a certain time, usually 2 hours before bed.
Support him and let him know he's a big boy now and its time to do big boy things.
Keep a really cute kid night light in the bathroom, some children are afraid of the dark and wont want to get up and use the potty. A night light will help.
I hope these help, but all kids are different. Good Luck:)