Sprinkle both sides of the chicken breast generously with Cajun seasoning. Heat the margarine in a skillet over medium-high heat. Add the chicken and cook for about 3 minutes; flip over and continue cooking until fully cooked through. Remove from the heat and slice lengthwise into 4 strips. Place on a baking sheet and spread the tomatillo sauce on top. Sprinkle with jack cheese and place in the oven to melt, just a couple minutes.
Meanwhile, spread the refried beans carefully over the taco shell, top with lettuce, rice, pico de gallo, and queso fresco. Remove chicken from the oven and place on top of fillings. Garnish with chives and a sprinkling of paprika. Serve with guacamole and sour cream on top.