Brown the ground chicken in a large skillet over medium-high heat. Drain off any excess grease.
Add the onion and bell pepper to the skillet and cook until softened, about 5 minutes.
Stir in the chili powder, cumin, diced tomatoes, and chicken broth. Bring to a simmer and cook for 10 minutes, or until the sauce has thickened slightly.
Warm the tortillas according to package directions. Fill each tortilla with the chicken mixture and top with shredded cheese.
Notes
Serve immediately. Garnish with your favorite taco toppings, such as sour cream, guacamole, salsa, or shredded lettuce.