Preheat oven to 375ºF. Melt butter (or heat olive oil) in large saucepan over medium-high heat; brown vegetarian crumbles 5-7 minutes. Add water and taco seasoning, then add tomatoes, black beans and corn. Stir until well blended then remove from heat.
Mix Bisquick, sour cream, eggs and 2 cups shredded cheese in bowl until well blended.
Grease 9"x13" pan; pour in bean mixture. Spread out Bisquick mixture evenly over beans. Bake for approximately 30 minutes, until top is golden.
Remove from oven. Sprinkle crumbled tortilla chips and remaining shredded cheese; bake 5 more minutes until cheese is melted. Top with sour cream and salsa, if desired.