Developer Options is gone, almost. It’s not just on Nexus 7 or Galaxy Nexus. Google has hidden the developer settings in the latest version of Jelly Bean, 4.2 for some reason. You can however easily enable it again.
Go to the settings menu, and scroll down to and click “About phone.”
Scroll down to the bottom again, where you see “Build number.”
Tap it seven (7) times. After the third tap, you’ll see a playful dialog that says you’re four taps away from being a developer. Keep tapping until the seventh time. Now you have access to Developer Options in Settings again. Go back into Settings under “System” between Accessibility and About tablet/phone you’ll have “Developer options”
A funny thing to notes is if you tab the “Build number” in “About tablet/phone” again you’ll get the message saying “No need, you are already a developer”