For Sauce: Place diced tomatoes, chipotle chiles and chicken broth in a blender; blend until smooth. Place sauce in slow cooker with turkey meatballs. Set on slow cooker on high, cover and heat for 3 hours.
To Assemble Tortas: Top each roll bottom with shredded lettuce, two turkey meatballs, drizzle with crema and garnish with cilantro. Serve warm on serving tray.