Add the chili powder, kosher salt, cumin, dried oregano, black pepper, onion powder, and garlic powder to a small bowl. MIx to combine.
Rub the spice blend into the country-style pork ribs and let them sit to come to room temperature for 15-30 minutes.
Spray the bottom of the slow cooker with cooking spray.
Add the chopped onions and garlic to the bottom of the slow cooker
Place the seasoned ribs on top of the onions in a single layer if possible.
Add the barbecue sauce and chicken broth to the slow cooker, pouring it over the ribs.
Place the lid on the slow cooker and cook the ribs on low for 3 -4 hours or until the ribs are tender, but not quite falling apart.*You can also cook the ribs on high for 1½ - 2 hours.
Remove the ribs from the sauce to a serving platter and cover with aluminum foil to keep warm.
Remove the sauce from the slow cooker and place it in a small saucepan. Skim off any excess fat from the sauce. Heat the sauce over medium-high heat to reduce until it has thickened. If needed, add additional barbecue sauce, or if it's too thick, thin it out with water or chicken broth.
Brush the ribs with the heated barbecue sauce and serve with your favorite side dishes.
If you want the ribs to be crispy and to caramelize the barbecue sauce, place them on a sheet pan under the broiler for 3-5 minutes or until they have crisped up to your liking. Just make sure not to let them burn.Brush with additional sauce and serve.