For the fresh slaw:
- Place fish in bowl with chili powder, minced garlic, salt, and black pepper and gently toss until fish is thoroughly coated in spice mixture.
- Add 1 tablespoon butter to a large nonstick skillet and heat over medium-high heat. Cook fish in two batches until just opaque and flakes easily with fork, about 4 minutes, turning halfway through cooking time. Transfer fish to a plate, heat remaining tablespoon of butter in skillet, and cook the rest of the fish.
- Heat the tortillas for 30 seconds on each side in a dry skillet or on the grill, until warm and pliable.
- Divide fish among tortillas and serve with toppings.
Add all ingredients to a bowl and toss to combine.
For the aioli:
Add all ingredients to a bowl and mix to combine.