I have definitely had bouts of nausea on LSD. Some quite severe.
Usually I wind up dosing an hour or two after I've woken up (around 11am-12pm... I tend to trip in the day), so I won't have had any food for twelve hours by that point. My stomach often feels "tight," like it's being twisted, slightly. By four or five hours into the trip, this is very pronounced. Pot usually helps alleviate these symptoms.
But I've definitely had intense moments of cramping/nausea/dry heaves, usually I believe because I hadn't really remembered to eat something. A light meal tends to make this go away.
I do find, however, that eating too much food on LSD can also lead to a really upset stomach. The first couple times, I decided around +7:00 or +8:00 that I should probably have some dinner, so I'd order a big meal (feeling hungry after all, since I didn't eat for several hours), and get a very upset stomach usually only part-way through the meal. I didn't usually finish eating a whole plate. I've since learned to stick to "easy" foods like fruits, yogurt, cream cheese, etc. and avoid meat/pasta/really heavy food.
Every other aspect of each of my trips meets a fairly standard LSD timeline. I have no reason to doubt the seller's claims that they were LSD. Sure as hell wasn't DOx. But the point of this longwinded defense is, LSD can include nausea, probably because you forget your body needs food.