The Nex boss is available in 2 wilderness locations, one in multi combat and another one single combat. Both of them have the same drop table, and same attacks (final nex phase). Keep in mind that the Nex boss is extremely difficult to challenge and it's levels (excluding hitpoints) raise based on the total number of attackers. There are semi-direct teleports to the boss via the Teleport Wizard. (::nexmulti & ::nex)
In order to access Nex's Prison, you must first pass through the Zarosian encampment. In order to do so safely, it is highly recommended that you wear a Zaros-affiliated item until you have passed safely beyond the essence-consuming door. Teleporting out of the arena will place you in this dangerous area, so it is recommended you keep this item with you at all times. For the purposes of the following section, consider the following:
In duos and trios, it is highly recommended for players that own one to bring an Elysian spirit shield, either to camp in ranged setups or as a switch, to mitigate damage and make the kill easier.
If using a crossbow setup, a Twisted bow with Dragon arrows should be brought to hit Fumus, Umbra, Cruor, Glacies and Blood Reavers. Your next best alternatives to the Twisted bow are either a Diamond dragon bolts (e) switch or a Toxic blowpipe with Dragon darts. A diamond bolt switch has the benefit of dealing more DPS than ruby bolts under ~ 350 HP, and just before Nex calls for a minion, where a ruby bolt proc would not be able to deal full damage. The Toxic Blowpipe is more useful against reavers and deals more DPS against minions close up.
At least two players (preferably all players) should bring a suitable stab or crush weapon capable of freeing their teammates from the ice prison special attack, the most common and affordable options are an Osmumten's fang or Zamorakian hasta set to stab, or a Dragon warhammer set to crush. If one cannot afford any of those, a Black salamander can be used to melt the prisons without the need for any ammo.
To significantly increase overall DPS, thralls are highly encouraged as they ignore Nex's defensive bonuses and count towards the player's kill contribution. Greater thralls require blood, cosmic, and fire runes in order to be summoned and should be put in a Rune pouch. If the player owns a Divine rune pouch, they can bring death runes and pick up the soul rune drops or bring a stack of them in the inventory for casting Death Charge to further boost overall DPS.
If utilizing the Zaryte crossbow special attack, you may add a Venator ring switch to your inventory only for your special attack. You should still camp your Lightbearer after special attacks as it deals more damage.
If using a hybrid setup, the Zaryte crossbow which is mainly used for the special attack in ranged setups, can be substituted for a Voidwaker instead as it requires less switches for slightly more DPS in melee gear. A Voidwaker should only be used if you have a Twisted bow or weaker crossbow such as an Armadyl Crossbow for a Ranged weapon, or you are attempting melee p2, as the difference between Voidwaker and Zaryte crossbow special attacks are minimal.
Ironmen or players on a budget can substitute a few Saradomin brews for hard food such as Anglerfish or Cooked karambwan, although brews increase the average kills per trip.
In larger team sizes where run energy may be an issue, it is recommended to drop one Saradomin brew for either a Stamina potion or the stackable Purple sweets to maintain run energy. Purple sweets can also be used to tick-eat certain portions of the fight.
The easiest way to fight Nex is to camp Ranged with the best crossbow you can get your hands on, as the gear is a lot cheaper and still almost as effective when compared to Hybrid setups utilizing Melee gear. Keep in mind that while Armadyl IS technically better than Karil's or Ancient d'hide, it's far less cost effective and you're better off saving to upgrade to each Masori piece individually and skipping the Armadyl armour altogether. The most important stats are your Ranged attack, Ranged strength, Magic defence, Crush defence, and Prayer bonus. Players with Dizana's quiver may prefer to instead camp the Twisted Bow against Nex, as it deals slightly more DPS than Zaryte Crossbow when charged in the best ranged setup and fully potted. A Zaryte Crossbow can still be used as a special attack, without needing a ruby bolt switch when using Dizana's quiver.
For more advanced Nexers, a Hybrid setup utilizing the Osmumten's fang as well as Torva is going to get you the best possible DPS on Nex. You can bring more or less switches depending on your team size and how comfortable you are with the fight. If you don't want to bring so many switches or are struggling to finish kills with supplies, it would be a good idea to drop the Torva platebody and platelegs and just camp the Masori body and chaps. For teams larger than 4 people, it's generally better to Ranged as the fight progresses quick enough and you can bring more supplies in to stay for several kills per trip, but for duos and trios, a Hybrid setup like the one below is going to get you your best possible DPS. It is highly recommended to be familiar with more advanced mechanics like resetting Nex's position or stalling/5-ticking in between your hits in order to slow down Nex's attacks as much as possible.
Slot
Item (most effective → least effective)
Torva full helm
Neitiznot faceguard
Slayer helmet (i)
Amulet of blood fury
Amulet of torture
N/A
Infernal cape
Fire cape
Max cape
Torva platebody
Masori body (f)
Karil's leathertop
Torva platelegs
Masori chaps (f)
Karil's leatherskirt
Osmumten's fang
N/A
N/A
Avernic defender
Dragon defender
Elysian spirit shield
Dragon arrow (if using a Twisted bow)
Ruby dragon bolts (e) (if using a crossbow)
N/A
Ferocious gloves
Barrows gloves
N/A
Primordial boots
Dragon boots
N/A
Lightbearer
Ultor ring / Venator ring (as a switch)
Brimstone ring / Berserker ring
Voidwaker (if not bringing a Zaryte crossbow)
Zaryte crossbow
N/A
Drops
The Nex drop table includes the Torva Armour, Zaryte Crossbow, Ancient Godsword & Zaryte vambraces.
You will receive a hidden 20% drop boost if you're skulled while killing Nex!
Armadyl helmet
Slayer helmet (i) / 
Ancient coif
Amulet of fury
Ava's assembler
Max cape > 
Ranging cape(t)
Armadyl chestplate
Karil's leathertop / 
Ancient d'hide body
Armadyl chainskirt
Karil's leatherskirt / 
Ancient chaps
Armadyl crossbow
Dragon hunter crossbow / 
Dragon crossbow
Elysian spirit shield (for duos/trios)
Spectral spirit shield (for duos/trios)
Ruby bolts (e)
Barrows gloves
Ancient bracers
Ancient d'hide boots
Archers ring (i)
Brimstone ring
Voidwaker (for guaranteed damage)
Toxic blowpipe (against reavers and minions)
