The dynamite Chicken Fajita marinade transforms the chicken into a juicy, flavor bomb worthy of the title "best Chicken Fajitas."  The marinade accomplishes three things:  1) tenderizes the chicken, 2) infuses it with flavor and 3) chemically changes its structure so it retains juices and actually becomes juicier.   I’ve outlined how the ingredients below adeptly accomplish this: Citrus:  orange juice and lime juice tenderize the chicken by breaking down the tough connective tissue. They also infuse the chicken with bright floral tones characteristic of Chicken Fajitas that complement the earthy seasonings.  Soy sauce:  enzymatically breaks down the proteins to further tenderize while also adding a rich depth of grounding flavor. Seasonings: the homemade fajita seasoning mix penetrates the chicken inside and out and is the perfect, robust blend. Oil:  is crucial as it spreads the oil-soluble flavors more evenly across the chicken and also promotes even browning when cooking.