Nick is the supervisor of the ominously-named Paddock 11, where the Indominus rex is kept.
Your typical working joe, he mostly just sits in the control room working at a computer and eating Oreos, but when it seems as though Indominus rex has somehow escaped, Nick is forced to get off of his fat butt and accompany chief animal handler Owen Grady into the enclosure to see how she managed to get out. Another worker, Ellis, goes with them.
While they're inspecting some claw marks on the wall trying to figure how Indominus got over it without anyone seeing her, Vivian Krill from the control room contacts them over Nick's walkie-talkie, frantically informing them that they just activated Indominus' tracking device...
...and she never left the paddock. She's in there with them.
Immediately the three men turn and begin running for the front entrance. Being a pretty big guy, Nick runs slow and lags behind.
He suddenly stops, glimpsing the dinosaur through the trees. Realizing she'll cut off their escape, he instead runs for the rear entrance, where he begins inputting his security code to get out. Owen and Ellis, who didn't see this, keep running the wrong way, only to get waylaid when the huge dinosaur appears between them and the door. Ellis is quickly eaten, while Owen runs full tilt towards the only other avenue of escape - the back door where Nick is.
Nick finishes inputting his code, and, turning and seeing Owen rushing towards him with the predator hot on his heels, freaks out and runs through the door before it even finishes opening and runs off. Observing all of this from the control room, Simon Masrani orders Lowery Cruthers to close the door, over his protests that it'll trap Owen inside with the beast. Nevertheless he obeys, and the door starts to close.
He manages to make it through and slides underneath a crane. The door doesn't close before Indominus gets to it, though, and she smashes through it. Free, she begins sniffing around. Owen looks over and is horrified to see Nick pitifully hiding by a pickup truck, almost entirely exposed.
It isn't long before Indominus finds him, flipping the truck over, exposing Nick sitting there frozen in terror.
He looks over at Owen under the crane, and their eyes meet just before the jaws come down and viciously tear Nick to pieces.
Owen can only watch in silent horror and continue hiding.