Pat the pork tenderloins dry with paper towels.
Mix the garlic powder, onion powder, thyme, rosemary, paprika, salt, and black pepper in a small bowl.
Rub the seasoning mixture all over the pork.
Heat the olive oil in a skillet over medium-high heat and sear the pork for 2 to 3 minutes per side until lightly browned.
Place the pork tenderloins in the slow cooker.
Whisk together the chicken broth, Worcestershire sauce, and minced garlic.
Pour the mixture around the pork.
Cover and cook on Low for 2½ to 3½ hours or until the pork reaches an internal temperature of 145°F (63°C).
Remove the pork and let it rest for 5 to 10 minutes before slicing.
For a thicker gravy, whisk together the cornstarch and cold water. Stir it into the cooking liquid and cook on High for 10 to 15 minutes until thickened.
Serve the sliced pork with the warm gravy spooned over the top.