Slice the bell peppers and onion and set aside.

Cut the chicken breast into strips and place in a bowl. Add the fajita seasoning into the chicken and stir to combine.

In a large cast iron, heat olive oil over high heat and cook the chicken strips until fully cooked. (About 6-8 minutes)

Remove the chicken from the cast iron and set aside. Then add in the sliced onions. Cook the onions until they become translucent.

Add in the bell peppers and cook them for about 4 minutes.

Place the cooked chicken back into the cast iron and cook with the bell peppers and onions for another 2-3 minutes.

Place the chicken and bell peppers into a flour tortilla and serve with sour cream.