With Marshmallow, this answer changes. Got to Settings / Security, as stated above, but look for "Lock Screen Message" instead of "Owner Info".
Android users with ICS and Jelly Bean can type and write some text to display on the lock screen. To customize or add owner info to lock screen on nexus 4 do as follows:
1. Open "Settings" app
2. Go to "Security"
3. Tap "Owner Info"
4. Type the text and mark "Show owner info on lock screen"
Update: If you have already updated to Marshmallow, look for the Lock Screen Message option, instead of the Owner Info.