On their corporate website they have an allergy list. Ironically the hardshell Taco corn shells have gluten but the nacho chips and potato oles do not. Adding this info since we were looking for it and couldn't find it. There are safe foods from an ingredient list standpoint but cross contamination may likely be an issue.
The hard shell tacos (beef and chicken) are GF. The chips are GF too (dedicated fryer). I have eaten hard shell tacos with pico de gallo and chips and cheese sauce here. I have never gotten sick.
The staff is friendly and knowledgeable so ask for the nutritional guide. Also, our cashier was well-trained and said he would make sure the order was gf. I only had chips and cheese sauce b/c I wasn't too hungry and was trying to fill hubby up.