game version: 1.16.5, mod version: 1.1.5c
When i add some items like minecraft:potion{Potion:"minecraft:healing"} in the cureitemlist , the game will always crash during loading.
Then i deleted what i had changed in the config, the game can start correctly.
i also have tested that the game with only this mod would crash after changing the cureitemlist

What does your config file look like?

#A list of items which can cure infection when 'consumed' or used on an entity can accept nbt tags. eg.minecraft:golden_apple, minecraft:potion{Potion: "minecraft:strong_regeneration"}
cureItemList = ["minecraft:golden_apple", "minecraft:enchanted_golden_apple", "minecraft:golden_carrot", "minecraft:potion{Potion: "minecraft:strong_regeneration"}"]

i only changed this in the hordes-common.toml,then my game crashed

Ah I see, the second set of " is what's causing the crash, replace the current potion entry with "minecraft:potion{Potion: "minecraft:strong_regeneration"}".

I'll update the description in the config to make it clearer that you need the backslashes.