Combine broth and tomatoes in a 1-cup glass measure; cover with heavy-duty plastic wrap, and vent. Microwave at high 3 minutes. Let stand, covered, 5 minutes. Drain tomatoes, and finely chop; set aside.
Place chicken and next 5 ingredients (chicken through pepper) in a 2-quart casserole, and stir well. Cover with heavy-duty plastic wrap, and vent. Microwave at HIGH 4 to 5 minutes or until chicken is done, stirring after 2 minutes. Add tomatoes, spaghetti, and cheese; toss well.