Gold stacking and lane sustain.
Creative tools and rule bending
Your first attack after using an ability on champions grants gold and sometimes consumables.
You get free boots at 10 min. but you cannot buy boots before then. These boots give additional MS. For each takedown you acquire the boots 30s sooner.
Get a free biscuit every 3 minutes, until 12 minutes. Biscuits heal and permanently increase your max mana.
+5% Max CDR
+5% Summoner Spell CDR
+5% Item CDR
35-300 health (at levels 1-18)
After 10 minutes gain 8 Armor and 8 Magic Resist and increase your total Armor and Magic Resist by 5%.
Heals and shields are 5% stronger and increased by an additional 10% on targets below 40% health.
Klepto on Nasus allows you to take short trades in lane with [Q] and whittle down your opponent through superior sustain.
Combined with the Bandit passive of Ancient Coin, you'll be making a ton of money in these short trades.
Magical Footwear allows you to double-down on that gold you're earning from Klepto and Coin by saving you a bunch of gold so that you're able to invest it into combat stats for the mid game.
Biscuit Delivery further empowers your ability to out-sustain your lane opponent and helps you survive in machups where you may take a lot of early game damage (Gnar/Rumble).
Cosmic Insight's well-rounded utility and free early CDR empowers your ability to build stacks as quickly as possible.
Conditioning makes you into a massive mid game front line tank as it will scale well with any defensive items you buy and continuing scaling into the late game with your infinite scaling damage.
Nasus is a champion who lives and dies by his ability to sustain with his passive. Revitalize massively empower that healing in the mid game where you'll be able to out-duel most other champions.
Patch 8.10 saw a buff to Phase Rush and jungle duels for scuttle making Xin a powerhouse.