Heat a large skillet over medium-high heat. Add the ground chicken, diced onion, and minced garlic. Cook until the chicken is no longer pink, breaking it up with a spatula. Drain any excess liquid.

Stir in the taco seasoning and water. Bring to a simmer and cook for 2-3 minutes, or until the sauce has thickened slightly. Remove from heat.

In a small bowl, mix together the plain Greek yogurt, lime juice, and chili powder until well combined.

Warm the large tortillas in the microwave for 15-20 seconds to make them soft and pliable.

To assemble, lay one warm tortilla flat. Spread about a tablespoon of the yogurt sauce in the center. Top with 1/4 of the chicken mixture. Place a tostada shell on top of the chicken. Spread another tablespoon of sauce over the tostada, then top with lettuce, tomatoes, and cheese.

Fold the edges of the large tortilla up and over the toppings, creating pleats, until the center is fully covered and sealed.

Lightly coat a skillet with cooking spray and heat over medium heat. Place the crunch wrap seam-side down and cook for 2-4 minutes per side, until golden brown and crispy. Repeat with the remaining crunch wraps.