In large bowl, pour margarita mix and 1/2 cup taco sauce over shrimp and toss well. Marinate in refrigerator for 30 minutes or up to 2 hours.
Preheat grill until sizzling hot, about 15 minutes. Grill shrimp 4 minutes on each side or until pink. Combine remaining 1/2 cup taco sauce with green chiles to use as a dipping sauce.