Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Line a baking pan with aluminum foil. Spray generously with cooking spray.
Combine Greek yogurt, mayonnaise, lime juice, onion, vinegar, cilantro, hot sauce, salt, and ancho chile powder in a bowl. Stir in shredded cabbage to make the slaw.
Place tilapia fillets on the prepared baking pan. Squeeze lime juice over fish. Combine cumin, paprika, salt, and garlic powder in another bowl. Sprinkle spice mixture over the fish.
Bake under the preheated broiler until fish flakes easily with a fork, 8 to 10 minutes.
Place tortillas between 2 damp paper towels. Warm in the microwave, 1 to 2 minutes.
Spoon the cooked tilapia onto each tortilla and top with the slaw.
