01 - Season diced chicken with salt and black pepper, ensuring even coating on all pieces.
02 - Heat olive oil in a large deep skillet over medium-high heat. Add chicken and cook until browned and cooked through, approximately 5 minutes. Transfer to a plate and reserve.
03 - In the same skillet, add onion and red bell pepper. Sauté for 2 to 3 minutes until softened. Add garlic and cook for 30 seconds until fragrant.
04 - Stir in risoni pasta and Italian herbs. Toast for 1 minute, stirring frequently to lightly coat grains with oil.
05 - Pour in chicken broth and milk. Bring to a simmer, scraping up browned bits from pan bottom for added flavor.
06 - Reduce heat to medium-low. Cover and simmer for 10 to 12 minutes, stirring occasionally, until risoni is tender and most liquid is absorbed.
07 - Return cooked chicken to skillet. Add spinach and stir until wilted, about 1 minute.
08 - Remove from heat. Stir in mozzarella and Parmesan until melted and creamy. Sprinkle with red pepper flakes if desired.
09 - Taste and adjust seasoning as needed. Serve hot, garnished with additional Parmesan cheese.