In a medium saucepan bring broth to boiling. Stir in millet. Return to boiling; reduce heat to medium. Cover pan, and cook 20 to 25 minutes or until millet is tender.
Meanwhile, preheat oven to 350°F. In a large saucepan cook onion over medium heat 7 to 8 minutes, stirring occasionally and adding water 1 to 2 tablespoons at a time as needed to prevent sticking. Add sage, thyme, garlic, pepper, and nutmeg; cook and stir 1 minute.
Dissolve the miso paste in ¼ cup hot water, and stir into onion mixture. Stir in ¼ cup of the tomato sauce and nutritional yeast, if using the yeast. Stir in cooked millet. Season with salt.
Immediately press mixture into a 9x5-inch nonstick loaf pan. Top with the remaining ½ cup tomato sauce. Bake 30 minutes or until heated through. Let stand 10 minutes before slicing.
