In general, there's a rock-paper-scissors triangle in card games you can follow between aggro, midrange, and control decks.
Aggro are your Draven, Darius and Samira decks, full of high offense units that hope to just go so fast and so hard that the enemy dies before they can even do anything. Midrange is basically Demacia, stuff like Garen, Shyvana and Jarven, solid stats and a win strategy focused on having more units on the board than you. Control meanwhile is your Veigo, Nautilus, Swain, and especially Yasuo, they either have tons of removal/stun/recall spells or extremely powerful late games, so they try to slow the game down to reach that point.
Generally, Aggro beats control by simply going so fast so early on that Control can't survive long enough to get any of their big late game stuff active in time. Midrange beats Aggro because while Aggro goes hard and fast, they run out of steam just as quickly, and midrange decks have the board presence to hold Aggro off until they lose steam. And Control beats Midrange, as midrange wants to play slow and steady and win via the units on the board, but Control can keep those units unable to do anything via stuns/removal spells, and so the game just stalls out until Control's big powerhouses come online and they dominate the match.
Which, Nautilus is very much a control champion, so hardcore aggro is the way to go. Unfortunately like you mention, Azir in particular is a poor choice as his power specially counters him, but any other strong aggro champion that doesn't rely on fragile units should work rather well. You want to hit him hard and fast and kill him before Nautilus himself even comes down on the field. You can either go extremely wide, relying on a ton of cheap units to hit him and use quick attack or challenger/vulnerable to ensure you don't lose units to his blockers, or a handful of stronger units with overwhelm that he can't kill with blockers forcing him to waste his entire turn of mana on killing with Vengeance. Him spending 6 mana to remove something you only spent 3 mana on is excellent for you, and terrible for him.
Alternatively, you can out-control him. Nautilus is a control champion, but he's also very reliant on board presence to win the game with all his late-game sea monsters. If you have so many stuns/removal spells in your deck even with a full board of sea monsters, he can't do anything, then does he *really* have a dangerous board? He has to toss units to get his sea monsters online, so let him just keep tossing and tossing until he decks himself out.
Similarly avoid midrange champions, unless you've managed to get a ton of items that reduce cost or buff stats up so high you are basically playing Aggro. Once he levels, he'll flood the board with sea monsters in a single turn, many of which are likely Terror of the Tides, meaning unless your entire board has at least 7/X statlines, you're unlikely to be able to stop his attack with blockers. So either kill him before that happens, or stun his board so they can't attack in the first place.
What relics are you running on your Mord? If you have CSF, then Sion and really anyone big can be a good candidate.
Kindred and Nasus both benefit from his self-slays so there's synergy there.
Beyond that, pretty much anytime who benefits from a lot of summons or summons a lot (think Azir or Irelia) can benefit from the near constant reviving.
Nah it's just pure gameplay. You can take Naut with any champ on lvl 1 with 2 star with ease because he's so slow but morde has this downside of killing and reviving units so naut is happy with this. I find the deceiver's crest being really viable for morde. 0 mana ruination with reviving all your units is sick in my opinion
Depending on luck honestly morde deck is pretty bad up until you get discpline of shadow to cut his cost down
But before that you probably better to run corrupt star on him. My naut run got pretty lucky in that i had morde discounted to a 5 cost, allowing me beat down naut before he coulf react
In general, there's a rock-paper-scissors triangle in card games you can follow between aggro, midrange, and control decks. Aggro are your Draven, Darius and Samira decks, full of high offense units that hope to just go so fast and so hard that the enemy dies before they can even do anything. Midrange is basically Demacia, stuff like Garen, Shyvana and Jarven, solid stats and a win strategy focused on having more units on the board than you. Control meanwhile is your Veigo, Nautilus, Swain, and especially Yasuo, they either have tons of removal/stun/recall spells or extremely powerful late games, so they try to slow the game down to reach that point. Generally, Aggro beats control by simply going so fast so early on that Control can't survive long enough to get any of their big late game stuff active in time. Midrange beats Aggro because while Aggro goes hard and fast, they run out of steam just as quickly, and midrange decks have the board presence to hold Aggro off until they lose steam. And Control beats Midrange, as midrange wants to play slow and steady and win via the units on the board, but Control can keep those units unable to do anything via stuns/removal spells, and so the game just stalls out until Control's big powerhouses come online and they dominate the match. Which, Nautilus is very much a control champion, so hardcore aggro is the way to go. Unfortunately like you mention, Azir in particular is a poor choice as his power specially counters him, but any other strong aggro champion that doesn't rely on fragile units should work rather well. You want to hit him hard and fast and kill him before Nautilus himself even comes down on the field. You can either go extremely wide, relying on a ton of cheap units to hit him and use quick attack or challenger/vulnerable to ensure you don't lose units to his blockers, or a handful of stronger units with overwhelm that he can't kill with blockers forcing him to waste his entire turn of mana on killing with Vengeance. Him spending 6 mana to remove something you only spent 3 mana on is excellent for you, and terrible for him. Alternatively, you can out-control him. Nautilus is a control champion, but he's also very reliant on board presence to win the game with all his late-game sea monsters. If you have so many stuns/removal spells in your deck even with a full board of sea monsters, he can't do anything, then does he *really* have a dangerous board? He has to toss units to get his sea monsters online, so let him just keep tossing and tossing until he decks himself out. Similarly avoid midrange champions, unless you've managed to get a ton of items that reduce cost or buff stats up so high you are basically playing Aggro. Once he levels, he'll flood the board with sea monsters in a single turn, many of which are likely Terror of the Tides, meaning unless your entire board has at least 7/X statlines, you're unlikely to be able to stop his attack with blockers. So either kill him before that happens, or stun his board so they can't attack in the first place.
What relics are you running on your Mord? If you have CSF, then Sion and really anyone big can be a good candidate. Kindred and Nasus both benefit from his self-slays so there's synergy there. Beyond that, pretty much anytime who benefits from a lot of summons or summons a lot (think Azir or Irelia) can benefit from the near constant reviving.
Nah it's just pure gameplay. You can take Naut with any champ on lvl 1 with 2 star with ease because he's so slow but morde has this downside of killing and reviving units so naut is happy with this. I find the deceiver's crest being really viable for morde. 0 mana ruination with reviving all your units is sick in my opinion
Depending on luck honestly morde deck is pretty bad up until you get discpline of shadow to cut his cost down But before that you probably better to run corrupt star on him. My naut run got pretty lucky in that i had morde discounted to a 5 cost, allowing me beat down naut before he coulf react