Add the reserved chicken-onion mixture, tomatillos, chicken broth, potatoes, oregano, and cinnamon stick to the pot and stir to combine. Bring to a boil over high heat, then reduce the heat to medium low and simmer, stirring occasionally, until the mixture thickens and the potatoes are tender, about 1 1/2 hours.Stir in the cilantro, taste, and season with salt as needed.Beverage pairing: With its combination of earthy vegetables and assertive spices, this dish calls for something a little exotic like the 2005 The FMC, an off-dry Chenin Blanc from South African master of the grape Ken Forrester. Complex with herbs, earth, fruit, and toast, the lightly oaked wine is a touch sweet, which will soothe any spiciness in the chile verde.