Place chicken thighs into a slow cooker. In a small bowl, combine cumin, salt, paprika, Mexican oregano, and chili powder. Sprinkle evenly over both sides of the chicken.
Add diced onion and jalapeños, then pour salsa and broth evenly over the top. Place lid and cook on low 6-8 hours.
When ready, remove lid and shred chicken using two forks. Serve with your favorite taco toppings.