Hey there. I also have a SUPER alert baby--strangers have always commented on how wide-awake and alert she is.
We have an absolutely black bedroom (I have a blackout curtain that I made of black felt) and we have always followed a pretty ironclad nap routine--go into room, diaper change, sleepsack (swaddled until 5.5 months), read stories, turn out lights, cuddle in rocker for 3-5 minutes, and into crib. No matter how wide awake she seems when we go into the room, she knows it's time for sleep and she does.
If babies are sleeping independently, most of the time nap problems are related to A times. What A times are you aiming for? 2-2.5 hours is pretty typical for his age, but if his first nap is quite short he could be overtired and need to go down for nap 2 earlier than normal.
Also, FWIW, when a baby fights a nap and then wakes early, it's often a too-short A time (too-long A times can cause short naps, but babies often conk out from being overtired, so they don't fight the nap as much).
HTH.