HEAT oven to 400°F.
COVER rimmed baking sheet with foil; spray with cooking spray. Mix coating mix and basil in shaker bag. Add fish, 1 piece at a time; shake gently until evenly coated. Place on prepared baking sheet.
BAKE 20 min. or until fish flakes easily with fork. Meanwhile, cook potatoes in boiling water in large saucepan 15 to 20 min. or until tender.
DRAIN potatoes. Add milk, Parmesan and cream cheese spread; mash until of desired consistency. Serve with fish.