Heat oven to 425ºF. Spray 2-quart casserole or 8-inch square glass baking dish with cooking spray. In casserole or baking dish, mix soup and milk until well blended. Stir in chicken, broccoli and pimientos.
Cover and bake casserole about 25 minutes or until bubbly.
About 5 minutes before removing casserole from oven, make biscuit mix as directed on package, using water. Drop dough by 8 large spoonfuls onto chicken mixture around the edges. Sprinkle with chives.
Bake uncovered 12 to 17 minutes or until bubbly and biscuits are golden brown.
High Altitude (3500-6500 ft): In step 2, bake about 35 minutes. In step 4, bake uncovered 17 to 20 minutes.