1. Combine kosher salt, pepper, garlic salt, chili powder, and paprika. Season the chicken legs with the spice rub and set aside.
2. Preheat a large frying pan over medium-high heat and brown the chicken legs in batches, about three to four minutes per side.
3. Spray the insert of a six-quart slow cooker with cooking spray (or line with a liner). Place the onion slices on the bottom of the pot. Neatly arrange the browned chicken legs over the onions. Spread the carrots and potatoes over the chicken.
4. Whisk the broth, wine, garlic, tomato paste, and thyme. Season with additional salt, pepper, and garlic salt, to taste. Stir in the cornstarch, then pour the sauce over
the chicken and vegetables. Press the bay leaf into the sauce.
5. Cover the slow cooker and bake on high for two to two and a half hours or on low for four to six hours.