Think about where both these players were in their careers and their opponents for context. If you're looking for the statistically worse performer, then yes, it's S1mple, but taking into account context, it's NiKo by a country mile, it's not even close.
NiKo was in his prime, that's it.
FaZe were a dominant #1
team and he was essentially afk against Cloud 9 who were dysfunctional at best then disbanded shortly after the major win.
2016 - For S1mple, Liquid was his first taste of Tier 1 cs. He'd had very little/ no useful experience being at the top playing in HR/ Flipside. Liquid had no business getting to the finals, let alone the playoffs. Liquid were ranked at #11
at the time, and this major had all the top 8 teams attending.
2018 - S1mple was indeed in his prime, but he was also playing against the best team of all time, who were notoriously good at shutting down star players, if you put NiKo in that situation he'd do exactly the same or worse. Yes, Na'Vi were second at the time, but being 2nd with this version of Astralis playing means absolutely nothing.
No one could do anything against this iteration of Astralis, 10 rounds in a game against them meant you were a top 5 team.