Cook ground been in a large nonstick skillet over medium high heat, stirring constantly to break up lumps, until no longer pink. Drain.

Add onion, bell pepper, garlic, chili powder and cumin to skillet. Cook over medium heat stirring constantly, until vegetables are softened, about 4 minutes. Stir in broth and tomato past; cook until liquid is almost evaporated but mixture is not dry. Transfer to a bowl and stir in 1/4 c cheese, the nuts, cilantro, sour cream and olives. Cool to room temperature.

Meanwhile, preheat oven to 400? and arrange rack in lower third of oven. Using 1 nonstick muffin pan, lightly coat with cooking spray. Unfold 1 piecrust on a lightly floured surface. using a floured rolling pin, roll out into a 15 inch then cut out 4 6 inch rounds. Fit into prepared pans. Prick bottoms of pie shells with a fork and freeze until firm, about 10 minutes.

Bake until golden, about 7 minutes. Transfer pie shells in pans to racks to cool. Divide filling between shells and top with remaining cheese. Bake in middle of oven until cheese is melted and filling is hot.