I chose this build, because is fast and it is a bit cheap. By using the Cloth Armor and the health Potions from the beginning, it grants longer laning time. With the health regeneration items is even better, plus the Heart of gold, which gives extra gold. The next step to create the Tanky Nautlilus is by Aegis of the Legion, and the Shirelia's reverie, because it give the nearby champs lots of bonuses, such as movement speed, armor and magic resistance. The Frozen heart gives 20% cooldown reduction which is great for a character like Nautilus, plus the armor and the mana. I chose the Warmorg, because it grants permanently health with every killed minion plus with each kill and assists it grants health regeneration. The Thornmail is kind of a smart step for a tanky character, because beside the 100 given armor, you return 30% damage!. Instead of the Warmorg's Armor you can use the Force of Nature giving even 40 health regeneration per 5 secs.
You can either sell the Heart of Gold, or upgrade it last
with Locket of the Iron Solari!
Thanks for using this build, i hope is helpful. JabariX