Doing all three Boss-fights back to back really shows how bad the Nihil fight is.
For this fight nothing you aquired in the game matters. Build, weapons, Frame choice, dont matter. (not even warframe passives help)
Unforgiving instant death. No time to learn or remember how to do this fight, while the machanics have nothing to do with the rest of warframes gameplay.
Throwing mechanic is clunky and slow and here the range feels extra short so you have to be pointblank.
The Boss sets the pace of the fight. You have to wait till he gives you the tools to defeat him. That's generelly hated game deisgn.
Falling doesn't matter in this supposed platfarming-fight. Losing platforms just makes it harder to deal damage tot he Boss, drawing out the fight.
In short: it's not hard, but very annoying and once you adapt to mitigate the issues with this fight it is just boring.