Nasus and the top lane

Ok, so I main adc as a rule, but whenever that is not available, I pref the top lane island, tanks being my second favourite thing to play.

For a long time, I had not seen someone play nasus in top for whatever reason, he just seems to have fallen out of favour.

Just played my last game as Olaf (vs a nasus) .

Now I get nasus is meant to be one of these super tanks, but as olaf early on, I should have had the advantage. (Ranged poke, true damage on the E etc.)

How wrong was I? Did I miss out on some secret nasus buff or has olaf been nuked into the ground recently? I mean seriously this nasus was able to just walk under my tower multiple times (bear in mind at the ealry stage of the game he only had a phage a sheen and ninja tabi, I had a vamp scepter, Ninja Tabi and tank runes/masteries)

I don't understand how someone with no defensive stats himself other than the ninja tabi (just like me) is able to stand under tower, whilst being hit by said tower as well as me using everything in my kit (full spell rotation, cutlass active) and still come out dead

It got to the point where I couldn't contest farm, so had to call for jungler to help multiple times, even then around the tower, he just went under, popped R and 2v1'd under tower.

Again, I know this is what nasus' kit is meant to do, but this was early on and for the first 15 minute we were even on farm and I had the overall lead, A tank is a tank, this guy was literally unkillable to the point where myself and the jungler were just left scratching our heads. (and the rest of the team flaming me for "feeding nasus", but seriously what do you do when he simply just walks under your own tower to kill you everytime he comes to lane?)

Needless to say, it was a loss, but my point being, I never remember him being THAT tanky, you used to be able to at least contest with him for a while, not just get rofl stomped under your own tower.

Anyone else had similar problems like this one? or was I just unlucky? lol