Add nil check after deserializing

init.lua

@@ -1516,6 +1516,7 @@ minetest.register_tool("fancy_vend:copy_tool",{
         local meta = itemstack:get_meta()
         local node_meta = minetest.get_meta(pos)
         local new_settings = minetest.deserialize(meta:get_string("settings"))
+        if not new_settings then return end
 
         if can_modify_vendor(pos, user) then
             -- Admin vendor priv check