Nathan is tall for his age, just like others in his class, such as Try, Memo, Amy Shtuzger, and Chelsea. However, in some appearances, he's pretty much in the exact same size as Dustin. Nathan has a cylinder-shaped head, and almost no hair but just a few strands in bang position. He has freckles near his ears, and razor-sharp buckteeth. He wears a blue shirt, darker blue pants and shoes the same colour as his shirt.
Nathan portrays himself to be bulky and buff but also dimwitted and oafish. In "Pretty Great Day with a Girl", he talks about how girls and boys "make-out", but clearly has no idea what it means. Another good example is in "Clarence's Millions" where he's shown to have failed a test despite claiming to have studied, even belittling himself by saying "I guess I am just dumb." On that note, it should be stated that contrary to what his appearance and his association with Belson would suggest, he's actually sensitive and kind in nature. When he failed his test, he feels really bad about it, but cheers up when Clarence gives him a Clarence Dollar. For his apparent lack of intellect, he's surprisingly constructive as he can be seen reading long books and is good at drawing. He also is willing to help others out and doesn't really bully at all. That said, he won't hesitate to get physical when people frustrate him. For instance, in "Zoo", he punches Percy and Breehn for ruining the class's day at the zoo, despite Breehn being on a stretcher with a swollen face.
Nathan, along with Dustin, is often seen hanging around with Belson serving as his right-hand men. While they often support Belson, like when they cheer for his story in "Honk", Nathan along with Dustin aren't completely loyal to him. A good example is in "Money Broom Wizard" where he calls Belson out for getting upstaged by Clarence in laser tag after Belson bragged about being the "Laser Ghost". Furthermore, although a friend of Belson, Nathan has been shown to get along well with Clarence and can be very helpful to him in situations. A good example includes "Pretty Great Day With a Girl" where he's seen enjoying a sandwich with Clarence and everyone else after the pine cone war. More notably, in "Clarence's Millions", he ditches Belson and follows Clarence around after being given Clarence Dollars and helps Clarence make a bully leave a nerd alone. He also helps Clarence make more Clarence Dollars and later helps him get the dollars to lose their value to end the anarchy they caused in the school. In "Belson's Sleepover", he is showing lack of intelligence when Belson pranks everyone by pretending to be a chainsaw killer, when obviously, the pranker was Belson. The only person who knew was Sumo.