Prepare grill for direct cooking over medium coals. Season tilapia fillets with oil and seasoning mix. Lightly grease grid of grill. Grill fillets, covered, 5-6 minutes or until tilapia flakes easily with a fork, turning once. Remove tilapia from grill.
Mash avocado in medium bowl. Stir in sour cream and 1/4 tsp of the salt; cover and set aside. Dice tomatoes; set aside. Snip cilantro and finely chop jalapeño pepper. Combine cilantro, jalapeno pepper, lime juice, remaining 1/2 tsp salt and garlic in large bowl; mix well. Add slaw mix and tomatoes; mix well.
Spread tortillas with avocado mixture to within 1 inch of the edge. Place 1 cup slaw down center of each tortilla and top with tilapia. Fold in ends of tortillas and roll up tightly.