Preheat oven to 350 degrees F.
Heat canola oil in a heavy nonstick saucepan. Add the ground turkey and break it up with the back of a wooden spoon Cook until all pink has disappeared. Pour out any excess grease. Add the onions, bell pepper, garlic, 1 teaspoon of the cumin, the chili powder and cocoa powder. Saute together until the meat and onions are well coated and the onions become slightly translucent. Add the espresso, tomatoes, stock and beans and stir well. Bring to a boil, then lower heat to medium and simmer, uncovered, for 1 hour or until thick.
Slice the tortillas into wedges and arrange onto a cookie sheet. Lightly sprinkle with the remaining cumin and place in oven until tortilla chips have crisped. Serve chili with tortilla chips and top with the Cheddar.