In a small bowl, mix olive oil, chili powder, cumin, salt, and pepper. Brush this mixture over the fish fillets.
Grill the fish for about 4-5 minutes on each side, or until cooked through and flaky.
While the fish is cooking, prepare the cilantro lime slaw by combining shredded cabbage, chopped cilantro, mayonnaise, lime juice, and honey in a bowl. Mix well and set aside.
Warm the corn tortillas on the grill or in a skillet for about 30 seconds on each side.
Once the fish is cooked, flake it into bite-sized pieces.
Assemble the tacos by placing the flaked fish on the tortillas, topping with cilantro lime slaw, and adding avocado slices.