Coat a 10-inch nonstick skillet with cooking spray; place over medium-high heat until hot. Add potato and next 3 ingredients; sauté 7 minutes or until tender. Remove from pan; set aside. Wipe pan with a paper towel. Combine egg substitute and next 4 ingredients, stirring well.
Coat pan with cooking spray; place over medium-high heat until hot. Pour half of egg mixture into pan. As mixture begins to cook, lift edges with a spatula, and tilt pan to allow uncooked portion to flow underneath. When set, spoon half of vegetables over half of omelet. Sprinkle vegetables with half of cheese. Loosen with spatula; fold in half. Cook 1 to 2 minutes or until cheese begins to melt. Slide onto a plate, cut in half, and keep warm. Repeat with remaining ingredients. Serve immediately.