Whisk together all marinade ingredients.
Place chicken strips in a container to marinate. Combine sliced onions and peppers in a separate container. Divide marinade evenly between both containers and toss well to combine. Marinate at least 30 minutes, up to overnight.
Preheat oven to 425 degrees. Remove chicken and vegetables from marinade and place on a sheet pan lined with foil. Bake 20 minutes, flipping halfway through, until vegetables are slightly charred and chicken is fully cooked. Serve on tortillas.