Quoting BOOSTIN HARD:
Usually valve seals are the indication when you let the car sit over night and when you first start it up it will smoke pretty good when you first start it.
This may be true in an older V8, but not really in our cars. The valve seal sits above the floor of the head, so oil doesn't pool up around them when the car is parked and not running. At idle, vacuum is what pulls oil past the seals and into the combustion chamber, causing the smoking issue. If it goes away after you leave a stop, it's most likely valve seals. It's a very common issue with the 4g63 when the miles start to climb.