Wait you sprayed the snake with "Nix" ?!?!?! How long ago was the last treatment?
Nix is not a "Spray on the critter" mite treatment its a spray the bedding and let dry kind of treatment.. If you did this before and not long ago then the animal is reacting to being sprayed with a pesticide.
How long ago was the last time you treated the animal and was it like today spraying the snake?