this way of playing nasus was invented by quas- ex lcs top laner. check his stream

standard way of playing nasus'd be to keep farming in the top lane, play super safe and stack your q damage while build full tank except for a triforce. eventually you'll become an unstoppable tank,a god who can walk over everyone and oneshot with a q, but at what cost?

-PRESSURE = your job is to safely farm and freeze top lane, u don't need ganks or kill in lane. you just want to stay safe and chill, eventually you'll get stacks and enough gold to become relevant, THIS means you will almost never tp somwhere other then top lane to reach your farm, also their top laner can push you and roam, finally if one of their lanes smash your's you become irrelevant, they will just hard carry enemy team before 30 min mark.

QUASUS IS THE COMPLETE OPPOSITE OF THIS PLAYSTYLE

so what is quasus?
QUASUS is based on this idea : if you lvl up your spirit fire (E) you will constantly push and outrade top lane ( that circle is as big as a wave of minions), leaving their team with 2 options: CAMP YOU OR LET YOU GET FIRST BLOOD TOWER.
what is this equal? PRESSURE: you become the exact opposite of a standard nasus, just keep pushing and but remember WARD river (you'll attract junglers as bees are attracted by honey).
IF YOU GET CAMPED? since you have warded u're safe, hey you are nasus- you have flash-wither(w)-plus sustain, even if you die just tp back and keep pushing!! here's a thing: since you apply so much pressure your team can safely stack drakes or focus mid-bot tower...hey junglers aren't omnipresent,something will be open, if their lee sin camps top this means easy drake, if their 4-0 diana Always roams top, mid tower and bot tower are exposed.
IF THEY JUST LEAVE ME ALONE? hey free tower first blood- 400G, say thank you and KEEP GOING.

WHY U MAX Q ON NASUS?
STANDARD NASUS just max his q, but WHY? why is standard nasus so weak early game?
the answer is TRADING: if you want to trade aerly game with standard nasus this involve using your q and e on enemy top laner, seems legit, but you'll find out it's never Worth: YOU NEED MANA to stack Q on minions, this is the biggest waekness of nasus: the spell you are maxing is used to farm! not to deal damage in trades

QUASUS MAX E : that circe deals a great amount of damage, shreds their defences and pushes the wave, have you ever played against ap nasus in aram? same stuff (remember you start with d ring :D), you'll get a lot of farm (just e their wave, EASY) ANYWAY, and meanwhile harass them.

pros and cons? STANDARD NASUS has a weak early, in Exchange for a superb late game when hopefully his team is not so far behind for basically playing 4 v 5, if he's well stacked and equiped he can carry his team
QUASUS has the most devastating early game- he just smash top lane and keeps a neverending shove BUT HERE'S THE THING: even quasus can reach a point in the game when he has stacks, cause it's a matter of time- sometimes you can kill a minion or 2 with your q and get your stacks.

summary:STANDARD NASUS:WEAK early, good mid game- GOD LATE
QUASUS: GOD EARLY- good mid- AVERAGE LATE- GOD HYPER LATEGAME(after 40 min mark)

START D RING AND POT: d ring gives you ap for spirit fire, MANA REGEN and hp, plus your passive gives you sustain. you out sustain- out damage and out push any top laner
first back get a second d ring and corrupting potion, now your sustain is of the roof, non can cope with you.
first buy get ZZ ROT: 24/7 afk push, just put it under your tower and spread the cancer- open d gatez
then build PURE TANK, become unkillable and keep shoving top lane- if they come top what do they get? u die but your team gets drake, gets a second tower, YOU APPLY PRESSURE.
at some point when you feel comfortable enough (even as a last item) get a TRIFORCE, boost your damage and mobility, which is essential for teamfights

remember that QUASUS is a team oriented pick- if get ganked and die to their jungler and your team doesn't do drake your Death is meaningless.
if you get first blood tower but their adc is 6/0 well...prey the god you can shove top quick enough and hope u can troll them and absue your lead, bring the to the top lane, your team can get bot tower while you just entertaint them.
BUT IF NONE OF YOUR LANE FEED TO HARD you got it!
shove top, keep going and join teamfights with tp, play him like a singed, or a trick2g's udyr, split and open d gatez.