Preheat oven to 400 degrees Fahrenheit.
Heat olive oil in large pan over medium-high heat. Once the oil is heated, add onion and cook, stirring occasionally, until golden brown (about 3 minutes).
Add salt, garlic, cumin, and paprika. Stir until aromatic (about 1 minute).
Add lamb, use wooden spoon to break up. Cook, stirring often, until cooked through and crisp (about 6 minutes). Remove pan from heat.
Spread half the tortilla chips on a rimmed sheet tray.
Top with 1 1/2 cups of cheese and half of the lamb mixture.
Top with remaining tortilla chips, remaining cheese, and remaining lamb.
Bake until cheese has melted (about 5 to 7 minutes). Remove from oven.
Top with green onion, radishes, banana peppers, cilantro, and sour cream. Serve immediately.