1. Mix pork, cilantro, and 1/2 cup tomatillo salsa.
2. In a 9- by 13-inch pan, mix tomato salsa and 1/2 cup broth.
3. In an 8- to 10-inch frying pan over medium-high heat, bring remaining 1/2 cup broth to steaming. Remove from heat. Dip 1 tortilla at a time in broth to slightly soften, about 1 second. As softened, lay each tortilla flat and spoon 1/8 of the pork mixture down the center. Sprinkle with about 1 tablespoon cheese, then roll tortilla to enclose filling. Set the enchilada seam down in the 9- by 13-inch pan. Repeat to fill remaining tortillas.
4. Spoon remaining tomatillo salsa over enchiladas, then sprinkle with remaining cheese.
5. Bake in a 400° oven until enchiladas are hot in the center and salsa is bubbling, about 30 minutes. Top portions with sour cream.