Place chicken in a Medium or Large Ziploc® Zip 'n Steam™ Bag. Seal bag. Pat chicken into a single layer and place bag in microwave. Cook on full power for 4 minutes (Medium bag) or 3-1/2 minutes (Large bag) or until meat is no longer pink. Chicken should be thoroughly cooked before adding remaining ingredients.
Allow bag to stand 1 minute before handling. Carefully open bag. Leave cooked chicken in bag. Add cheese, pizza sauce, flour, oregano, garlic powder and salt to bag. Seal bag and gently shake to combine ingredients. Pat ingredients into a single layer and place bag in microwave.
Cook on full power for an additional 1-1/2 minutes to melt cheese and make sauce. Allow bag to stand 1 minute before handling. Wearing an oven mitt, gently squeeze bag to combine cheese sauce. Carefully open bag and serve.