Instructions

1. Arrange a rack in the middle of the oven and heat the oven to 375°F. Line a rimmed baking sheet with aluminum foil.
2. Make the walnut meat:
3. Place 1 1/4 cups California walnuts in the bowl of a food processor. Drain and rinse 1 (about 15-ounce) can chickpeas and add about half (3/4 cup) to the food processor. Pulse until coarsely chopped, about 6 (1-second) pulses.
4. Finely grate the zest of 1 medium lemon until you have 1 teaspoon. Juice the lemon until you have 3 tablespoons. Add the lemon zest, 1 tablespoon dried oregano, 1 tablespoon olive oil, 1 teaspoon garlic powder, 3/4 teaspoon kosher salt, and 1/4 teaspoon black pepper to the food processor. Pulse, stopping to scrape down the sides and bottom of the bowl as needed, until the mixture is finely chopped, about 10 (1-second) pulses.
5. Make the nachos:
6. Prepare the following, adding each to the same medium bowl as you complete it: Halve 1 cup grape or cherry tomatoes. Halve 1/2 cup pitted kalamata olives. Small dice 1/2 small English cucumber (about 1 cup). Add the remaining chickpeas, 1 tablespoon of the lemon juice, 1 tablespoon of the olive oil, and 1/2 teaspoon kosher salt. Stir to combine.
7. Arrange 1 (7 to 9-ounce) bag pita chips on the baking sheet and bake until warm, 4 to 5 minutes. Meanwhile, heat the remaining 1 tablespoon olive oil in a large skillet over medium heat until shimmering. Add the walnut meat and cook until browned and crisped in spots and warmed through, 6 to 8 minutes.
8. Mix 1 cup tzatziki sauce with the remaining 2 tablespoons lemon juice and spoon over the chips. Top with the walnut meat. Use a slotted spoon to top the nachos with the chickpea and veggie mixture, leaving any liquid in the bowl. Sprinkle 1/2 cup crumbled feta cheese over the top and serve immediately.