Tablets work well put in a small dob of butter, cottage cheese, peanut butter or hidden in a small pice of chicken, bread,ham, fish etc. hot dogs also,work really well, especially heated up, as the smell hides the tablet more.
For liquids, either squirt the syringe directly into the mouth, from the side, so it goes straight down the throat before it can get a chance to be spat out, or mix it into a plain yogurt, potted meat, tin of tuna.
I would never ever use chocolate spread

. The amounts of chocolate needed to cause harm varies a lot, both in the side of the dog and the chocolate itself, but putting tablets in chocolate spread on a regular occurrence ( worming tablets for instance), is not going to be doing any good,and could cause a lot of harm over time.