In large bowl, combine orange juice, zest, garlic, cumin, salt, and oregano. Add chicken; stir to combine. Cover, and refrigerate for 1 hour to marinate.

In large skillet, heat butter over medium-high heat. Add onion and peppers; sauté 2 to 3 minutes. Using a slotted spoon, add chicken to skillet, discarding any remaining marinade. Sauté 8 to 10 minutes, or until chicken is cooked through, stirring frequently. Transfer chicken and vegetables to large warm serving platter. Sprinkle 1/2 cup of queso blanco and cilantro over the top.

Roll a portion of the mixture in warmed tortillas. Serve with the remaining cheese, shredded lettuce, salsa, guacamole, and sour cream.