Spray 8-inch square (2-quart) glass baking dish with cooking spray. In 10-inch skillet, cook sausage over medium-high heat 5 to 7 minutes, stirring occasionally, until no longer pink; drain.
In large bowl, mix sausage and remaining ingredients except salsa. Pour into baking dish. Cover; refrigerate at least 8 hours but no longer than 24 hours.
Heat oven to 350°F. Bake uncovered 50 to 60 minutes or until knife inserted in center comes out clean. Serve with salsa.