I would suggest drop the weird nob as you dont even have enough orks on the bord to give him a casting buff. Id say either
Swap ardboys for another grunter unit to tie up ranged units
Remove weird nob and ardboys get a fungoid shaman, gruntas, cogs
Or double down on the shaman swap ironfist for weirdfist, swap the gruntas for boys to trigger your caster buff and be close to the nob, remove warchanter and get a balewind so you can spell spam.