Where cbu meets drywall - finishing

OK. Thanks to all for the help. So far; so good. Now, the cbu is in, nice and level and square - I reckon this helps final tile stability and appearance. The question today is; how to finish the vertical joint where the cbu and drywall (on the walls adjacent to the shower). There was standard drywall corner bead under bullnose tiles when I pulled out the old shower. Should I reinstall corner bead and skim coat the outer edge? If so, I assume I use the Hardieback screws to attach the bead to the cbu and drywall nails to attach the opposite side to the drywall - then thinset and bull nose back on the tile side. Thanks, Tom