Pre-heat oven to 375 degrees.
Brush both sides of pita bread triangles with olive oil and place on a baking sheet. Sprinkle with salt and pepper. Bake pita chips for 8-10 minutes, until lightly golden.
In a large pan over medium heat, add olive oil and cook onion and garlic until softened and fragrant, about 5 minutes.
Add lamb to pan and sprinkle on coriander, cumin, oregano, salt, and pepper. Cook, breaking up with spatula, until no longer pink.
Arrange chips into nacho formation and crumble feta cheese in between layers and on top.
Broil for a couple minutes until feta gets melty. Top nachos with lamb and then sprinkle on chopped tomato, cucumber, and kalamata olives. Spoon hummus and Greek yogurt onto nachos for maximum scooping potential. You can sprinkle more feta over the top if you want, too.