In medium saucepan over medium-high heat, pour broth, then add 1 can water and bring to boil. Add chicken, reduce heat and simmer 12 minutes. Remove from heat and let cool in poaching liquid, about 15 to 30 minutes. Shred chicken using two forks. Preheat oven to 400°F. In large bowl, combine chicken, salsa, cumin, oregano, cheese and onions, then divide into six portions. Place one portion filling in center of tortilla; fold left and right sides of tortilla over filling, then fold tops and bottoms over sides to form square, securing with toothpick if necessary. Repeat for remaining tortillas. Place each tortilla seam side down on baking sheet and brush with olive oil. Bake 25 minutes, or until golden brown. Garnish with cheese, onions, salsa and lettuce, if desired.