Some chips are made with Olestra--even though not marked as such. Practically all corn (tortialla) chips, organic or not are GMO because of cross pollination. This causes IBS among other problems.
Olestra is a fat substitute used in crackers and potato chips, marketed under the brand name Olean. This synthetic fat is not absorbed by the body (instead it goes right through it), so it can cause diarrhea, loose stools, abdominal cramps and flatulence, along with other effects. Further, olestra reduces the body's ability to absorb beneficial fat-soluble nutrients, including lycopene, lutein and beta-carotene.