Yes, it is possible to overdose on nuts. Consuming too many nuts can result in adverse health effects due to their high calorie and fat content, as well as the potential for certain types of nuts to contain high levels of certain minerals and compounds.
One reference to support this claim is a study published in the Journal of Clinical Lipidology in 2015. The study found that excessive consumption of nuts, particularly macadamia nuts and Brazil nuts, can lead to elevated levels of certain minerals such as selenium, which can have toxic effects on the body if consumed in excess. Additionally, the high calorie and fat content of nuts can lead to weight gain and other health problems if consumed in excessive amounts.
Reference: Griel, A. E., Eissenstat, B., Juturu, V., & Hsieh, G. (2015). A review of the safety and efficacy of nuts consumption in the US. Journal of Clinical Lipidology, 9(6), 825-846. doi: 10.1016/j.jacl.2015.07.002