Pat the chicken legs dry with paper towels.
In a small bowl, combine kosher salt, black pepper, garlic powder, smoked paprika, dried thyme, onion powder, and cayenne pepper.
Rub the spice mixture evenly over all sides of the chicken legs.
Heat olive oil in a large skillet over medium-high heat.
Sear the chicken legs in the skillet for 2-3 minutes per side until golden brown. This step is optional but adds extra flavor.
Transfer the seared chicken legs to the slow cooker.
Pour the chicken broth into the slow cooker around the chicken legs.
Cover and cook on low for 4 hours, or until the chicken reaches an internal temperature of 165°F (74°C) and is tender.
Carefully remove the chicken legs from the slow cooker and serve hot.