I vape nic salts in all my tanks, and I DIY with nic salts at 18 m.g. You can definitely use a Nautilus 2 with nic salts, depending on how high the juice is in mg/ml. You don't need a pod system. With the 1.8 coil though, I'm betting you could go fairly high. Or really any other MTL vape you desire.
Heck you can use Sub0hm equipment (at the right dosage strength, like 3--6 mg) but you can most definitely use it in a Nautilus 2. If it feels too "strong" for you, could use slightly less high mg/ml nic salts, or just vape less.
Nic salts aren't dangerous, and I don't really know where this "pod mod only" stuff is coming from, other than it's "marketing" pod mods as the Juul has been so successful.
You can use nic salts just the same as regular nicotine, it's simply dose dependent like any other form of nicotine. If you are worried, pay an eye to nicotine overload and put down the vape. But it vapes like any other juice, just less throat hit, slightly different taste, and CAN be raised to ungodly levels due to lack of throat hit, but does not NEED to be.
Best of luck, I would choose an N2 topper over a pod mod for your trials, most definitely.
Anna