Heat 1 tbsp olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Season chicken pieces with 1/2 tsp salt, 1/4 tsp black pepper, 1/2 tsp garlic powder, and 1/2 tsp onion powder. Add chicken to the pot and cook for 5-7 minutes, stirring occasionally, until browned and cooked through. Remove chicken from the pot and set aside. Once cool enough to handle, shred or dice the chicken.

Reduce heat to medium. Add 1 tbsp olive oil and 2 tbsp butter to the same pot. Once butter is melted, add the finely chopped yellow onion and cook for 5-7 minutes until softened and translucent, scraping up any browned bits from the bottom of the pot. Add minced garlic and cook for another 1 minute until fragrant.

Sprinkle in 1/4 cup all-purpose flour over the onion and garlic. Whisk constantly for 1-2 minutes to create a roux, cooking out the raw flour taste.

Gradually whisk in the 6 cups of chicken broth, ensuring no lumps form. Bring the mixture to a gentle simmer, stirring occasionally. Once simmering, add 1 cup milk and 1/2 cup heavy cream. Stir well.

Stir in dried oregano, dried basil, red pepper flakes (if using), 1/2 tsp salt, and 1/4 tsp black pepper. Bring the soup back to a gentle simmer.

Add the broken lasagna noodles to the simmering soup. Cook for 8-10 minutes, or according to package directions for al dente, stirring frequently to prevent sticking. The noodles should be tender but still have a slight bite.

Return the cooked chicken to the pot. Add the fresh spinach and stir until it wilts, which should take 1-2 minutes.

Remove the pot from the heat. Stir in 1/2 cup grated Parmesan cheese and 1 cup fresh mozzarella cheese until melted and fully incorporated, creating a creamy, cheesy broth.

Taste and adjust seasonings as needed. Serve hot, garnished with fresh chopped parsley and additional Parmesan cheese, if desired.