Slice the chicken breast into thin strips and place them in a bowl.
Toss the chicken with olive oil, chili powder, cumin, garlic powder, sea salt, and black pepper until evenly coated.
Preheat a grill pan or outdoor grill over medium-high heat.
Grill the chicken for 3 to 4 minutes per side until deeply charred and cooked through.
While the chicken rests, finely shred the red cabbage and dice the white onion and avocado.
Place the corn tortillas on the grill for 30 seconds per side until they are warm, pliable, and slightly toasted.
Assemble the tacos by dividing the grilled chicken between the two tortillas.
Top each taco with the shredded cabbage, diced onion, avocado slices, and fresh cilantro.
Squeeze the juice from the lime over the tacos just before serving for a bright, acidic finish.