Wich difficulty you are you playing on? If your problem is nurse call herself, I think you just need to increase your stats, I'm not sure but maybe percentage-damage reduction might help against her (you get a ring for that from the sackhead girl, give her a viscera or kill her)
Also, as far as I remember, you need to dispel the requiem on the zombies and Nurse call to be able to kill them, undead killer mushrooms helped too
If you are still having too much trouble, just spam requiem while using Node's clock to recharge the skill, as long as you have enough clocks, you'll eventually kill them, just remember to re-apply the buff ~2 turns BEFORE it ends, otherwise you'll die if you have 0 life.
Latter dlc bosses made me go crazy, 40k on all stats and they still managed to instantly destroy me on difficulty one.