Double-up the square foil pans (that is, insert one inside the other). Add in the pork, onion, ½ cup (125 mL) BBQ sauce, tomatoes and beef broth. Stir well. Cover doubled pans tightly with foil.
Place on upper rack of grill preheated to medium-high. Cook 10 min.; reduce heat to low. Maintain temperature at 325°F (160°C); cook 2 hr. or until meat is very tender.
Wearing oven mitts, carefully open foil. Spoon pork and sauce into large bowl. Using 2 forks, shred pork. Stir in Swiss chard, red pepper, corn and remaining BBQ sauce; spread in foil pie plate. Cover with rolled pie crust. Use tines of fork to crimp edges of crust and adhere it to plate edge. Make 3 small slashes in centre of crust. Whisk egg with 1 tbsp (15 mL) water; brush over crust.
Place on upper rack of barbecue on medium-high heat. Cook with lid closed. Adjust flame as needed to maintain temperature of 425 °F (220 °C). Cook 25 to 30 min., or until filling is bubbling and pastry is golden brown.
Double recipe to make a second pie at the same time, or make just the filling to use in gourmet sandwiches.