Detachment choice for new list

Running a new list for an upcoming game against my Ork player mate. Just wondering what detachment works best for this lay out. I'm feeling pactbound zealots but I'm open to other options. I did have another list with 2 warpsmiths with an additional destructor and no nurglings. Last game we played he had nothing but killer Kans and a Morkanort. Kinda wanna hit back with some big hitters this time.

I have also thought about changing out the sorcerer and nurglings for a lord in Terminator armour, but held off for the potential for secondaries with the nurglings.