Toast pepitas in a dry skillet over medium heat for 3 minutes, stirring, until fragrant. Transfer to a blender with tomatoes and juices, onion, garlic, raisins, cocoa, ancho powder, cumin, cinnamon, salt and broth; blend until smooth.
Pour the sauce into a 4-quart slow cooker and add chicken breasts, turning to coat. Cover and cook on high for 2 1/2 to 3 hours until the chicken reaches 165°F.
Lift chicken onto a plate and shred. Return it to the sauce and cook covered on high for 10 minutes.
Toss cabbage with lime juice, keeping it separate from the hot chicken.
Warm tortillas in a dry skillet over medium heat for 20 to 30 seconds per side.
Serve one-quarter of the chicken mole and cabbage with 2 tortillas per portion.