Brazil nuts-can they set you off with allergic response?

Yes: One can be allergic to brazil nuts. Typically these tree nuts cross react with other tree nuts as well (walnut, cashew, pistachio, and many others). If you think you had an allergic reaction after eating brazil nuts, see an allergist to get tested so you know what foods to avoid, and so you can have an emergency plan (with the right meds) in case you have a life-threatening allergic reaction.