Preheat oven to 350°F.
Prepare a baking sheet with parchment paper and cooking spray.
In a large bowl, combine shredded chicken, quinoa, black beans, corn, tomatoes, red onion, garlic, chili powder, onion powder, and garlic salt. Mix well.
Cut each bell pepper in half lengthwise.
Spoon mixture into bell peppers until just a little over full. Top with cheese.
Place in the oven and bake for 10 minutes.
Remove and top with cheese. Return to oven for an additional 10-15 minutes, or until peppers are soft when poked with a fork.
Remove from oven and top with avocados and fresh parsley.