In 12-inch nonstick skillet, cook bacon until crisp. Drain on paper towels. Crumble bacon; set aside. Reserve 1 tablespoon bacon drippings in skillet. Add mushrooms to drippings; cook 4 to 5 minutes or until tender, stirring frequently. Remove from skillet; set aside. Wipe skillet clean with paper towel.
Melt margarine in same skillet over medium heat. Beat eggs in large bowl. Add half-and-half, salt and pepper; blend well. Add egg mixture to skillet; cook over medium heat until firm but still moist, stirring occasionally. Stir in soup and chives.
Place half of egg mixture in 3 1/2 or 4-quart slow cooker. Top with half each of the cooked mushrooms, tomatoes, cheese and crumbled bacon. Repeat layers.
Serve immediately, or cover and keep warm on low setting for up to 4 hours.