[Nautilus] is among the top 3 sentinels in the game ([Nautilus], [Diriga], [Wyrm Prime]). That's thanks in no small part to [Cordon], probably the best sentinel precept.

[Cordon] clumps enemies together, it has a great 30m range and pulls enemies pretty hard. When combined with manifold bold to reduce it's already short cooldown, it'll feel like having your own personal larva [Nidus]. Unfortunately, [Cordon] doesn't apply status through [Manifold Bond], so in order to keep it running you will need some status on your weapons.

Just like any other sentinel with powerful precepts and [Manifold Bond], [Mystic Bond] and [Guardian] are incredibly powerful. Granting tons of extra energy economy, and tons of free shield refills for shield gating.

Overall [Nautilus] is a top pick for a sentinel, its very consistent, and unlike [Wyrm Prime] or [Diriga], it doesn't require certain weapon types to hit it's max potential. It's certainly a great option as a generalist "use with everything" companion although it's tough to recommend over a [Smeeta Kavat].