Nishinoya can hiss, and he can hiss well. In fact, one time, Kenma hissed at him while they were at a training camp, and he hissed back, and they had a hissing battle for a solid ten minutes until Yaku and Suga managed to break them up.

Nishinoya can also scream-hiss, and its fucking terrifying. He did it in front of Asahi once and he cried.

The legendary hissing battle. Notice Kenma T-posing to assert dominance, and Nishinoya pulling a Peridot.

SU fans will get that last one.