Cook rice blend according to package directions; drain and set aside.
While rice blend cooks, combine flour and 1/2 cup milk; stir until smooth. Combine flour mixture, remaining 1 cup milk, salt, pepper, and hot sauce in a medium saucepan; stir well. Cook over medium heat, stirring constantly, until mixture is thickened and bubbly. Remove from heat and add cheese; stir until cheese melts.
Combine rice blend, cheese mixture, and beans in an 11- x 7- x 1 1/2-inch baking dish coated with cooking spray. Combine breadcrumbs and chili powder; sprinkle over rice mixture. Coat with cooking spray and microwave at HIGH 9 minutes or until thoroughly heated.