Heat tortillas as directed on package; keep warm.
Meanwhile, heat 10-inch nonstick skillet over medium-high heat. Add chicken; cook and stir 1 minute. Stir in bell pepper and chili powder. Add water; cover and cook 2 to 3 minutes, stirring occasionally, until chicken is no longer pink in center and bell pepper is crisp-tender.
Spoon chicken mixture evenly onto warm tortillas. Top each with 2 tablespoons cheese and 1 tablespoon sour cream. Fold in 3 sides of each tortilla to enclose filling. Wrap each wrap securely with foil; take with you for an on-the-go dinner.