Pat the chicken legs dry and drizzle with olive oil.
In a small bowl, combine the onion powder, garlic powder, paprika, Italian seasoning, Kinders Grilled Chicken Seasoning, and chicken bouillon powder. Season the chicken generously on all sides.
Sprinkle the flour evenly over the bottom of your slow cooker.
Slowly whisk in the chicken broth until the flour is mostly combined.
Add the diced onion and green bell pepper to the slow cooker.
Place the seasoned chicken legs on top of the vegetables.
Dot the chicken with the butter.
Cover and cook on High for 4–5 hours or Low for 6–7 hours, until the chicken is fall-off-the-bone tender.
Gently stir the gravy before serving. Spoon the onions, peppers, and gravy over the chicken.