Preheat the oven to 375°F (190°C).
Heat olive oil in a large skillet over medium heat. Add diced onion and cook for 3 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add cubed chicken breasts to the skillet. Cook for 6-8 minutes, stirring occasionally, until chicken is no longer pink on the outside.
Add diced red bell pepper and broccoli florets to the skillet. Cook for an additional 5 minutes until vegetables are slightly tender.
In a large mixing bowl, combine cottage cheese, Greek yogurt, shredded cheddar cheese, chicken broth, dried thyme, dried oregano, black pepper, salt, and crushed red pepper flakes. Mix well.
Transfer the cooked chicken and vegetable mixture into the mixing bowl with the cheese and yogurt mixture. Stir until everything is evenly combined.
Pour the mixture into a greased 9×13 inch casserole dish and spread evenly.
Sprinkle grated Parmesan cheese evenly over the top of the casserole.
Bake in the preheated oven for 30 minutes until the casserole is bubbly and the top is golden brown.
Remove from the oven and let it rest for 5 minutes.
Garnish with chopped fresh parsley before serving.