Pat the chicken thighs dry with paper towels.
In a small bowl, mix together salt, black pepper, smoked paprika, garlic powder, onion powder, dried thyme, and dried oregano.
Rub the spice mixture evenly over both sides of each chicken thigh.
Heat olive oil in a large skillet over medium-high heat.
Add the chicken thighs skin-side down and sear for 3-4 minutes until the skin is golden brown. Flip and sear the other side for 2 minutes.
Remove the chicken thighs from the skillet and set aside.
Place the sliced yellow onion and minced garlic in the bottom of the slow cooker.
Pour the chicken broth over the onions and garlic.
Place the seared chicken thighs on top of the onion and garlic mixture in the slow cooker.
Cover and cook on low for 6 hours until the chicken is tender and cooked through (internal temperature should reach 165°F or 74°C).
Once cooked, remove the chicken thighs from the slow cooker and let rest for 5 minutes before serving.