Heat gas or charcoal grill. Carefully brush vegetable oil on grill rack.
Place corn directly on grill over medium-high heat. Cover grill; cook 8 to 10 minutes, turning occasionally, until lightly browned on all sides.
Meanwhile, in small bowl, mix melted butter, lime juice and 2 teaspoons taco seasoning mix; set aside. In custard cup, mix queso fresco and chives; set aside.
Brush cooked corn with butter mixture; sprinkle with queso fresco mixture. Serve hot.