In previous Android builds the Developer Options was in Settings>scroll to near bottom and there is was. Now in 4.2, that setting is gone. Well not really. It IS gone from plain sight, but it is still there. Seem those crafty OS builders decided to hide it from you.
All you have to do is go to Settings>About Phone/Tablet (this is for N4 and updated N7 too) and click on the Build Number a few times --->[Think about when you are mashing the screen to find the Easter Egg. It is similar to this]. It should start counting down. Repeat the process until it states, "You are now a developer". Then you can back out to the main page of Settings and your Developer Options should now be there.
Please note, I said Build Number and NOT Android Version
Good Luck and Happy Developing