Salsa Verde with milk

1 lb large shrimp , peeled and deveined 2 tablespoons olive oil 1 tablespoon lime juice 1/8 teaspoon ground black pepper 1 large onion , chopped (about 1 cup)[...]

4 tablespoons butter 1/2 cup all-purpose flour 14 1/2 ounces chicken broth 15 ounces salsa verde (about 2 cups) 5 ounces evaporated milk 1 large rotisserie[...]