It DOES look like pests. Nutrient burn is possible, but only if they grew like that right away. But if the leaves were fine one day and looked like this the next day, I would have expected nutrient burn to have left some brown or yellow around the holes.
Personally, my guess would be moths. While they are the easiest to see, if you're looking for little critters, moths are easy to miss. Opening your tent while it's dark and turning a lamp on outside of the tent for a few minutes may draw them out. Do this immediately at lights out or right before lights on so you don't stress your plants at all.
Also looks like you have or did have N toxicity at some point. Your leaves are rather dark. Good luck!