Chicken and Bell Pepper Fajitas

4 skinless boneless chicken breast halves
5 tablespoons vegetable oil
1/4 cup fresh lime juice
1 tablespoon minced garlic
1/2 teaspoon salt
1/4 teaspoon ground pepper
10 (6-inch) flour tortillas
1 large red onion, sliced
1 large red bell pepper, cut into 3/4-inch-wide strips
1 large yellow or green bell pepper, cut into 3/4-inch-wide strips

Using meat mallet, lightly pound chicken between sheets of wax paper to thickness of 1/2 inch.

Mix 2 tablespoons oil, lime juice, garlic, salt and pepper in large glass baking dish. Add chicken and turn to coat. Cover and refrigerate at least 30 minutes or up to 1 hour.

Preheat oven to 350 degrees F.

Wrap tortillas in foil. Heat in oven until warmed through, about 10 minutes. Turn oven off. Leave tortillas in oven.

Heat 2 tablespoons oil in heavy large skillet over medium-high heat. Add onion and saut