In a large mixing bowl, combine the Greek yogurt with turmeric, cardamom, cinnamon, paprika, cumin, and sea salt. Add the chicken to the bowl, tossing it to ensure the pieces are evenly coated in the spice mixture.

Preheat your oven to 400°F, positioning the rack in the center of the oven. Line a large, rimmed sheet pan with parchment paper for easy cleanup.

Prepare the fresh vegetable topping by mixing the diced Roma tomatoes, onions, garlic, parsley, cucumber, Peppadew peppers, and lemon juice in a medium bowl. Season the mixture with salt to taste.

Arrange the seasoned chicken pieces on the prepared sheet pan and bake for 18-20 minutes. Ensure the chicken reaches an internal temperature of 165°F when checked with an instant-read thermometer. Once done, remove the chicken from the oven, discard the parchment paper, and let the chicken rest for 5 minutes before slicing into thin strips or bite-sized pieces.

On the same sheet pan, lay out a single layer of tortilla chips. Add one-third of the chicken and one-third of the feta cheese on top. Repeat with the remaining chips, chicken, and feta, creating multiple layers. Return the pan to the oven and bake for an additional 10 minutes, allowing the cheese and chicken to warm through.

While the nachos bake, prepare the tahini sauce. In a medium-sized bowl, whisk together tahini, lemon juice, garlic, water, and salt until the mixture is smooth. If the sauce begins to separate, continue whisking until fully emulsified.

Once the nachos are ready, top them with the tomato-cucumber mixture and Peppadew peppers. Drizzle the tahini sauce over the top and serve the nachos warm.