CVar nameplateAllowOverlap

Controls whether nameplates over units in the 3D world are allowed to overlap.

Default setting

 * 1

Possible settings

 * 1 :Enabled. Nameplates may overlap, and will stay more or less directly above the units they represent.
 * 0 :Disabled. Nameplates may not overlap, and will be constantly shuffled around to fit on the screen while remaining as close as possible to their units.

Changing this setting
In-game, type the following /console nameplateAllowOverlap 1

Alternatively, you can exit wow, open the Config-cache.wtf file, and add the following line: SET nameplateAllowOverlap 1