Cook pasta as directed on package.
Meanwhile, heat oil in large nonstick skillet on medium-high heat. Add cauliflower; cook and stir 5 min. Remove from skillet; cover to keep warm. Add chicken, in batches, to skillet; cook 3 min. or until evenly browned, stirring frequently. Return all chicken and cauliflower to skillet; cover. Cook on medium-low heat 2 min. or until heated through, stirring occasionally.
Drain pasta, reserving 1-1/2 cups cooking water. Return pasta to pan; stir in reserved water and Singles. Cook on medium heat 2 min. or until Singles are completely melted and sauce is well blended. Add to chicken mixture in skillet with mozzarella; cook 2 min. or until mozzarella is melted, stirring frequently. Sprinkle with parsley and Parmesan.