Slice the chicken breast into thin, bite-sized strips and place them in a medium mixing bowl.
Season the chicken with chili powder, cumin, garlic powder, sea salt, and black pepper, tossing until every piece is evenly coated.
Heat the olive oil in a large cast-iron or non-stick skillet over medium-high heat until shimmering.
Add the chicken to the hot pan and sear for 5-7 minutes, stirring occasionally, until the edges are golden brown and the meat is cooked through.
While the chicken cooks, whisk together the lime juice and chopped cilantro in a bowl, then toss in the shredded cabbage to create a bright, zesty slaw.
Warm the corn tortillas in a separate dry skillet for 30 seconds per side until they become soft and pliable.
Assemble the tacos by dividing the spiced chicken between the two tortillas, topping with the crunchy cabbage slaw, and finishing with slices of creamy avocado.