Cut bell peppers in half lengthwise; discard seeds and membranes. Arrange halves in a 9-inch pie plate. Cover with heavy-duty plastic wrap. Microwave at high 5 minutes or until crisp-tender; drain. Return peppers to pie plate.
Combine chicken and Cajun seasoning in a bowl. Heat the oil in a medium saucepan over medium heat. Add the chicken; sauté 4 minutes or until done. Remove from pan.
Add onion and garlic to pan; sauté 1 minute. Add broth, rice, and salt; bring to a boil. Cover, reduce heat, and simmer 15 minutes. Return chicken to pan; cover and cook 3 minutes or until rice is done. Stir in spinach and chives. Divide the rice mixture evenly among pepper halves.