I went thru a lot of Nautilus coils, but only because I used 5 of the tanks with different juices and vaped heavily for months with them. The only time I got a dry hit was when I wasn't paying attention and let the tank run dry.
When I swapped out a coil I would change the coil and fill the tank. Then with the tank I would cover the air holes with a finger and take a few good draws WITHOUT POWER to create suction and pull the
juice into the wick. After each draw I would check to see the air bubbles from the wick holes. I repeated this process 3 or 4 times. Then I usually let the tank sit for 5 minutes. It worked for me.
It's possible you have gotten some bad coils. I never "cleaned" my coils until they were gunked up. Even when swapping
juice I would clean the tank and just use a paper towel to wipe off the bottom part with the coil. Usually after 3 or 4 hits with the new filled tank the old
juice flavor disappeared as the new juice was wicked into the coil. I would still take a few unpowered draws for prime to be on the safe side.
After a coil got "gunked up" I would take it and put it in a small glass jar with some vodka and let it soak for a few days to a wee, giving the jar a shake every now and then. Then I would take the coil out, blow it off and let it air dry for a day as the vodka evaporated. It didn't make the coil like new but I did get a lot more mileage out of them. The Nautilus coils can be rebuilt/coiled, check you tube if interested.