Easily missed as it's too irresistable to create a Mutant BBQ than do the trophy.
On your Normal run, it will take three hits to kill a Nosalis. The first wave is the easiest.
The best advice for a Normal run I can give is when you reach the big red door in the Garage in the bunker. Find the lever that reboots the power in the booth to your right, but save it first.
If you get through the first wave having to use your flamethrower rather than punching them. Reload the save.
It's a lot easier doing this on an reader run through, if you struggle to do the Blind one trophy on Normal, you can do both on reader.
There's a great solution to that above, Make sure you try and stick to the middleish though and give yourself some space to the walls.