Preheat oven to 375°F. Mist 2 mini-muffin tins with cooking spray.
In a bowl, combine first six ingredients. In a separate bowl, beat eggs with buttermilk and oil. Pour egg mixture into flour mixture and stir to form a thick batter. Fold in cheese and chilis.
Spoon enough batter to half-fill 24 cups in mini-muffin tins. Bake until a toothpick inserted into center of a muffin comes out clean, about 15 minutes. Cool in pans on wire racks for 5 minutes, then turn muffins out onto racks to cool further. Serve warm or at room temperature.
