Quite a few use rokkits from the special weapon sprues. Easy peasy. I found myself short a couple so I used rokkits from the dakkajet kit and added them in various ways to the boys and loaded them heavy with tankbombs Just to mix things up I posed them differently:
Now the Nob needs to be the big ol bully in this unit. I use a cut down AoBR Warboss for the body, cutting into the shoulders to narrow them a bit. A standard nob head and arms to keep the proportions correct, and the use of Kan Rokkit launchers make it clear who da boss. A suitably decorated bosspole and mounting on the correct sized base (unit leader, not a "Nob" model) and they are ready to go.