My mini nautilus does get quite hot when I'm chain vapeing. Around the bottom of the
tank and eventually can start to gurgle. Does it do any damage if it's getting hot. ?
Gurgling could be due to a multitude of reasons, when I started off as a vaper, I had issues with gurgling especially when I was chain vaping and eventually found out with experience that it was because I was drawing really hard whenever I was chain vaping. I still find it quite hard today to take slow and gentle draws today when I chain vape, especially when drunk

.
I now vape on different tanks, sometimes on clearomizers like your mini nautilus, and sometimes on my kayfuns, and I have found that the smaller devices get warm to the touch MUCH quicker than the larger kayfun. Whenever it gets too warm I usually swap devices or set it down for a while mostly because I do not want to cause pre-mature damage to my O-Rings or seals. Also on the smaller devices, the seals usually sit really close to the coil itself.
I take a vape once a minute, give or take, and have found no adverse effects on myself. When I over do it I get the similar sensation that I used to get when I would chain smoke 3 cigarettes in a row, lightheaded and some nausea, the sensation is less pronounced, but that is when I would set it down for a while until I feel a craving.
Hope this helps!