first im not saying he wanted to be the igl but the situation that made him to be. and the second based on what ur saying "OG brougt him as a rifler" means OG planned him as the rifler at first but bcs valde changed his mind he will be the igl, OG didn't lying right? if valde didnt changed his mind, nexa wont be the igl. it's not that OG planned to scam him to be igl at first.
if i were on that situation i have two choices, which one do i care the most? myself or the company?
if i care myself the most, i would resign and move to another company, but if i care about the company i would take that job bcs i understand not everyone capable of doing ceo works.
these situation is quite similiar with nexa situation. if he want to be happy he could terminate the contract especially since hes not announced yet or if he's think that the team success are what matters, he could take that roles bcs there are not many good igl out there and he understand that he is one of the best igl. if he's a bad igl OG wont asked him to be the igl, they could just forced niko to be igl.