Hi.

This season, I reached D4 as support and decided I would rather touch grass than keep playing League. However, while touching grass, the Church of Doggo gave me a divine revelation that I feel obligated to share.

This build hinges on a few interactions:

Fimbulwinter and Solstice Sleigh are triggered when a Melee champion applies a slow. This build gives Nasus multiple ranged, point-and-click slows. They're triggered by these two (skill-intensive) combos:

Nasus W
Nasus E, Rylai's Scepter

Phase Rush is triggered by the application of 3 AutoAttacks, Damaging Abilities, Item Effects, Summoner Spells, Crowd Control, and Damage over Time. This means Phase Rush is triggered by these combos:

W, AA, Q
W, E, Q
W, E, Ult
W, E, Rylai's Scepter + Imperial Mandate

The combination of Solstice Sleign + Imperial Mandate lets Nasus provide significant engage for his team while Rylai's Scepter + Nasus E gives significant disengage.

This build wants to stack ability haste to maximize the uptime on Nasus's W and E.

At Level 8 with Ionian Boots and Fimbulwinter, Nasus will have 53 ability haste. This puts his E on a 7.8 second cooldown. His E lingers for 5 seconds, giving it a ~64% uptime.

With Rylai's Scepter, any enemy who walks in the circle will suffer from a 45% armor reduction and a 30% slow. This will deter most enemies when placed at a chokepoint. In team fights, Nasus will Ult to peel the enemy frontline, E to zone the enemy backline, and save his W for high-priority targets.

In terms of damage, Nasus Ult does a minimum of 3% Max HP magic damage per second, up to a total of 45% Max HP, with additional synergy from Rylai's Scepter.

At full build, Nasus will have a total of 93 ability haste and 50 item haste.
These will be his ability cooldowns:

W- 5.7-second cooldown with a 5-second slow, for an 88% uptime.
E- 6.2-second cooldown with a lingering 5-second zone, for an 81% uptime.
Ult- 41.4-second cooldown (at max rank) with a 15-second buff.

These will be his item cooldowns:

Solstice Sleigh: 20 seconds, providing a 2.5-second speed boost.
Fimbulwinter: 5.3 seconds, providing a 3-second shield.
Imperial Mandate: 6.0 seconds, providing a 2-second speed boost.

This build lacks the DPS and durability to 1v1 the enemy ADC. Instead, you should use your Ult + W to lock down the enemy frontline and your E to zone the enemy backline.

The combination of Solstice Sleign + Imperial Mandate gives you 45% bonus movement speed.