After replacing my oil cap three times in the past 18 months due to it continuously slipping out, Hall Nissan today finally agreed to order me a new valve cover assembly.
At first the service rep said he would not cover it under warranty. The warranty guy said he had no clue, and finally the service manager said he would get Nissan to cover it under "good faith." Whatever that is.
So, thank you Hall, although it is about time.

Oh yeah, the problem lies within the long tube between the oil cap and the valve cover. The threads are toast at the top 1" of the tube. Get this, the service rep said he had no idea how that could happen, and that just taking it off for oil changes could not have done that. He was hinting that it could have happened from offroading. Yeah, when monkeys fly out of my butt.