Great news Hon.
I would still be offering a nap and even is he refuses you may just go for quiet time, maybe cuddling on sofa with you when you watch a DVD and he nods off. It's great he can catchup after a NND, but it's worth mentioning that when some kiddos may go from napping to no napping in one day, some will need a transition period and a NND firstly once a week, than twice, every other day etc. Try to remember how it was with 2-1 transition - did he go through it just like that or was is a long process?