Meanwhile, heat oil in a frying pan over medium heat. Add onion, capsicum and zucchini. Cook for 3 minutes. Add chilli powder and cook, stirring, for a further 2 minutes. Add tomato and cook, stirring, for 2 to 3 minutes or until soft. Add corn, beans and salt and pepper. Remove from heat and stir to combine.
Grease a large baking dish. Place 1/4 cup filling on 1 warm tortilla (keep remainder wrapped in foil as you work). Roll up. Place, seam side down, in baking dish. Repeat with remaining tortillas and filling.
Spoon taco sauce over tortillas. Sprinkle with cheese. Bake for 10 to 15 minutes or until cheese melts. Serve immediately.
Roll tablespoonfuls of mixture into balls and place on baking trays lined with non stick baking paper, pressing down on the tops to flatten slightly.