1 red onion, sliced in thirds
1 green bell pepper, sliced in quarters
4 boneless, skinless chicken breast halves
4 corn tortillas, warmed
1 1/2 cups shredded cabbage
1 (14.25 ounce) can colada and burrito pepper mixes with liquid
1 (15 ounce) can jalapeno peppers, drained
1 (15 ounce) can sliced mushrooms, stemmed
1 1/2 cups shredded Taco Bell pepper mixture
1 tablespoon margarine