I have an itchy throat after eating cashews, what could be wrong? what are the chances of it itchy due to nut allergy?

Extremely high risk: Itchy throat is highly suggestive of a food allergy, and the next exposure could lead to worse symptoms (swollen throat and inability to breathe). So, definitely eat no more nuts of any kind until tested for allergy. If your are having symptoms now, get medical help if you feel swelling in the throat or tongue. This is an appropriate use of an er if necessary.