Nasus Runes explained
There's one set of runes for Nasus on patch
11.8
that is the clear favorite for LoL players and pros alike. The best Nasus Runes on the position 
Top are Precision as the primary path and
Inspiration as the secondary path with a pick rate of 62%. Besides runes you should take a look on Nasus Build and if you are interested in pro matches take a look at Nasus Probuilds. If you want to discuss
Nasus then you should visit the champion subreddit.
Primary path on Nasus
Precision improves attack and sustained damage on Nasus troughout the match. Most of high elo players – and our LoL pros in the the major regions – have agreed that
Fleet Footwork is the best keystone rune to run on
Nasus. This keystone rune generates you a lot of sustain and increases your survivability against poke champions in lane. This is usually followed up by taking
Overheal,
Legend: Tenacity and
Last Stand.
Overheal converts healing in excess of maximum health of Nasus into a shield, which provides additional safty and tankiness. Nasus gains extra Tenacity with every additional stage of
Legend: Tenacity. With
Last Stand you deal more damage while you are at low health.
Secondary path on Nasus
When it comes to your secondary path, most
Nasus players prefer to go with
Inspiration.
Inspiration opens creative opportunities on Nasus troughout the match. On the
Inspiration path, the best runes for Nasus are
Approach Velocity and
Biscuit Delivery.
Nasus gains bonus movement speed by
Approach Velocity, while moving toward enemy champions that are immobilized or slowed. This rune is perfect to follow up engages by your teammates.
Biscuit Delivery is a great rune for laning as it gives additional health and mana, which can help in more aggressive lanes.