Do Nike sneaker sizings run small? As in... if I'm a size 7.5'ish normally, would a 7 fit me? (UK sizes)?

if it's only half a size difference, you'll be ok. they might get a bit tight if you're walking/ running a lot because your feet swell, but that would happen with any shoes. i wear shoes half a size too small most of the time and i haven't had any problems, so you'll be fine. go for it, get them