Pat the chicken tenderloins dry. In a shallow bowl, mix the all-purpose flour, Italian seasoning, salt, and black pepper. Dredge the chicken in the seasoned flour until evenly coated.
Melt the butter in a skillet and add the onion and bell peppers. Sauté for about 2 minutes until they start to soften, then add the minced garlic and cook for 1 minute.