Nex seems to be extremely popular in the game. Every OSRS gold update needs to gain 75 percent approval from users before going live. Nex was approved by an overwhelming 90 % of players deciding to add her in.
Anyone with membership at any level is able to take on the boss, however Jagex suggests the following levels: 70 Ranged, 70 Strength 70 Agility, 70 Strength, 70 Hitpoints. It is also required that you have completed The Desert Treasure quest, so you'll have access for the Frozen Door. The door will be used to access Nex's domain and allow you to attempt and kill the monster yourself.
As you'd expect from any good boss game, there's incredible loot to be snatched up. Jagex hasn't revealed too much detail regarding what to expect, but it has revealed that among the items that are up to grabs is an Ancient Godsword, Zaryte crossbow and the Torva armor set.
If you'd like to test this expansion out for you, Old School cheap RS gold is free to play on both PC and mobile. The expansion is only available to players with a paid subscription.