In a bowl, whisk olive oil, lime juice, chili powder, cumin, paprika, garlic powder, onion powder, salt, and pepper. Add chicken and toss to coat; marinate at least 20 minutes (up to 2 hours).

Make the slaw: toss cabbage with lime juice, olive oil, a pinch of salt, and half of the cilantro. Set aside.

Stir the Baja sauce: mix sour cream (or Greek yogurt), mayonnaise, lime juice, remaining cilantro, garlic powder, and hot sauce or minced jalapeño if using. Chill until serving.

Heat a grill pan, outdoor grill, or large skillet over medium-high. Lightly oil the surface and cook chicken 5–7 minutes per side, until charred in spots and cooked through (165°F/74°C). Rest 5 minutes, then slice thinly.

Warm tortillas in a dry skillet or microwave until soft and pliable.

Assemble tacos: layer sliced chicken in tortillas, add slaw, drizzle with Baja sauce, and top with avocado and extra cilantro if desired. Serve immediately with lime wedges.