Preheat the oven to 450 degrees. Mix the tilapia fillets in a shallow bowl with the taco seasoning and the olive oil. Place in the fridge, and let the fillets marinate for 15-20 minutes. Once marinated, take the tilapia out of the bowl and place it into a glass casserole dish. Roast in the oven for 15 minutes, or until the fish starts to flake easy with a fork. Serve on warmed tortillas with avocado slices, shredded cabbage, queso fresco, pico de gallo, and slices of lime.