Heat oven to 350°F. Cook bacon in skillet until done but not crisp. Carefully remove grease from skillet. Add mushrooms and bell peppers to skillet; sauté until tender-crisp.
Meanwhile, beat together eggs and milk. Stir in bacon, mushrooms, peppers, mexi-corn, muffin mix, cheese and green onions. Pour into greased 11x7x2-inch baking dish.
Bake in 350°F. oven for 35 to 40 minutes or until knife inserted in center comes out clean. Let stand 10 minutes before serving. Serve topped with salsa.