Pat chicken dry with paper towels and season with salt and pepper. Heat 1 tablespoon oil in 10-inch nonstick skillet over medium-high heat until just smoking. Lay chicken in skillet and cook until well browned on first side, 6 to 8 minutes. Flip chicken, reduce heat to medium, and continue to cook until chicken registers 160 degrees, 6 to 8 minutes. Transfer chicken to cutting board, tent loosely with aluminum foil, and let rest while preparing vegetables.

Add bell pepper, onion, water, chili powder, and ¼ teaspoon salt to now-empty skillet and cook over medium heat until vegetables are softened, 5 to 7 minutes; transfer to serving platter.

Meanwhile, whisk lime juice, cilantro, Worcestershire, brown sugar, ¼ teaspoon salt, and remaining 1 tablespoon oil together in large bowl. Cut chicken into ¼-inch-thick slices and toss with lime juice mixture. Arrange chicken on platter with vegetables and serve with warm tortillas.