Three brand-new Nexus 4 accessories are appearing on the US Play Store (UK, Canada, and Germany too) today: a wall charger, a microUSB cable, and a set of earbuds with a built-in microphone. The wall adapter is a rather steep $16, the microUSB cable $10, and the earbuds $20.
Basically, you're probably vastly overpaying for all of this stuff, should you so choose to invest in it - 2.1A wall adapters (with two outlets, no less) can be found on Amazon for $10, and microUSB cables for a few bucks at Monoprice. But if you really need the official gear, it's there now.
The headphones don't appear to be anything special, though they are kind of neat looking, and have a tangle-resistant flat cable with an in-line microphone, so that's a plus. Still, I'm not typically in the 'let's buy some unbranded, generic headphones!' kind of mood. These seem like the sort of thing you'd bundle with a phone, not that you'd buy separately. But hey, they're there if you want them. The wall charger and the USB cable are... well, they're what you get in the Nexus 4 box. Head to the Play Store to check the new Nexcessories out.