Chrome released a new feature maybe three or four weeks ago to split screen two tabs within your window with the Alt+Shift+N keyboard shortcut which now conflicts with yours.
Chrome doesn't let us change the native shortcuts. Not in any way I'm familiar with. And you don't seem to have any user-configurable options where this is concerned. Would like to see that added to your platform. I suppose is the resolution here so that the non-Chrome users who are probably unaffected by this conflict don't have to adjust to a new shortcut
