Preheat your oven to 375°F.
In a large skillet, heat the olive oil over medium heat.
Add the sliced onions and sauté until they are caramelized, about 15-20 minutes.
Stir in the garlic powder, thyme, salt, and pepper, and cook for an additional minute.
In a 9x13-inch baking dish, place the chicken breasts in a single layer.
Pour the beef broth over the chicken, then spread the caramelized onion mixture on top.
Spoon the French onion dip evenly over the onions, then sprinkle with shredded Swiss cheese and breadcrumbs.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 15-20 minutes, or until the chicken is cooked through and the cheese is bubbly and golden.
Let the dish rest for 5 minutes before serving.